Evaluation of Clinical Outcomes and Acceptability of an Anatomical Classification for Placenta Accreta Spectrum, a Multicentric Prospective Cohort Study
Conditions: Placenta Accreta
Sponsor: Fundacion Clinica Valle del Lili

 
 
EVALUATION OF CLINICAL OUTCOMES AND 
ACCEPTABILITY OF AN ANATOMICAL 
CLASSIFICATION FOR PLACENTA ACCRETA 
SPECTRUM, A MULTICENTRIC PROSPECTIVE 
COHORT STUDY 
 
 
 
 
Principal investigator: Albaro José Nieto-Calvache1 
 
 
 
 
 
 
 
 
1Fundación Valle del Lili, Departamento de Ginecología y Obstetricia, Clínica 
de Espectro de Acretismo Placentario, Cra 98 No. 18 - 49, Cali 760032, 
Colombia 
 
 
 
 
FUNDACIÓN VALLE DEL LILI, CALI, COLOMBIA  
FEBRUARY  2023 
 
 

 
1 
 
 
 
Principal Investigator: 
Albaro Nieto-Calvache 
Research Contributions: Protocol, 
data collection, article writing. 
Contact: +57 (2) 331 90 90 Ext. 4022 
 albaro.nieto@fvl.org.co 
Affiliation: Fundación Valle del Lili, 
gynecology and obstetrics department, 
placenta accreta clinic. 
(Corresponding author) 
Subinvestigator : José Miguel 
Palacios Jaraquemada 
Research Contributions: 
Protocol, data collection, 
article writing. 
Contact: 
jpalaciosjaraquemada@gmail.com 
Affiliation: Department of Obstetrics 
and Gynecology, Durand Hospital and 
the School of Medicine, University of 
Buenos Aires, Buenos Aires, Argentina 
Methodological Advisor: Juan 
Sebastián Galindo 
Research Contributions: Protocol, 
statistical analysis, methodological 
review 
Contact: juan.galindo@fvl.org.co 
Affiliation: Fundación Valle del Lili, 
Clinical Research Center 
Co-Investigator 1: Daniela 
Sarria- Ortiz 
Research Contributions: Protocol, 
data collection, article writing. 
Contact: daniela.sarria.or@fvl.org.co 
Affiliation: Fundación Valle del Lili, 
clinical research center, department of 
gynecology and obstetrics. 
Co-Investigator 2: Laura Muñoz- 
Cordoba 
Research Contributions: Protocol, 
data collection, article writing. 
Contact:laura.munoz.co1@fvl.org.co 
Affiliation: Fundación Valle del Lili, 
clinical research center, department of 
gynecology and obstetrics. 
Keywords 
Keywords: Placenta Accreta; Anatomy, 
Regional; 
Classification; 
Pregnancy 
Outcome 

 
2 
 
 
 
 
TABLE OF CONTENT 
INTRODUCTION 
3 
THEORETICAL FRAMEWORK  
4 
Definition 
4 
Traditional classification 
4 
Topographic classification 
8 
JUSTIFICATION FOR THE STUDY  
11 
RESEARCH QUESTION 
11 
RESEARCH HYPOTHESIS 
11 
OBJETIVES 
12 
General 
12 
Specific 
12 
EXPECTED RESULTS 
12 
METHODOLOGY 
12 
Design 
12 
Study population 
13 
Centers involved 
13 
Criteria for choosing the centers invited 
13 
Patient admission criteria 
14 
Inclusion criteria 
14 
Exclusion criteria 
14 
Data collection techniques 
16 
Data Management and Statistical Analysis 
16 
Table of Variables 
19 
Blank Tables 
23 
OPERATIONAL ASPECTS  
28 
SOCIALIZATION OF RESULTS  
29 
ETHICAL CONSIDERATIONS  
29 
SCHEDULE 
33 
REFERENCES 
35 
ANNEXES 
38

 
3 
 
 
INTRODUCTION 
The incidence of placenta accreta spectrum (PAS) has hiked up, directly proportional to 
the increased frequency of cesarean section (1). As the name implies, the condition 
includes a spectrum of various clinical presentations, from "mild" forms, which if 
managed by expert groups can have intraoperative risks similar to cesarean section; to 
very severe forms that can lead to death and require both great surgical skill and the use 
of multiple healthcare resources (2). 
The classification of PAS adopted by the International Federation of Gynecologists 
(FIGO) is based on the degree of penetration of the placenta into the myometrium. 
Therefore, its histologic staging is only possible by analyzing a tissue sample after surgery 
and does not contribute to surgical decisions. In addition, histological analysis is seldom 
available in center with limited resources (3). 
Among the characteristics expected to be found in a classification applied for a disease 
that is managed surgically, its application prior to surgery (based on imaging studies) and 
its confirmation during laparotomy, are ideal. Additionally, such a classification should 
make it easier to choose the treatment option and correlate with the clinical results or the 
degree of surgical difficulty. An interesting proposal for PAS is the topographic 
classification created by Palacios - Jaraquemada et al (1), with 5 differentiated categories 
based on the part of the uterus affected and the possibility of separating or not the uterus 
from the bladder. This classification has been studied and successfully implemented by 
hospitals in low- and middle-income countries, and retrospective studies have been 
carried out describing its correlation with clinical results and the usefulness of one or 
another surgical technique (1,4). Currently there are no prospective multicentric studies 
that address the relationship between this anatomical classification with clinical variables, 
and no study has reviewed the opinions of the professionals who use it. 
We propose the execution of a prospective multicentric study consisting of a cohort of 
patients with prenatal or intraoperative diagnosis of PAS, evaluating the clinical outcomes 
of the group of patients found in each category of the topographic classification. In 
addition, an approach to evaluate the acceptability of this classification among the 
obstetrician-gynecologists of the participating medical centers will be included.

 
4 
 
 
THEORETICAL FRAMEWORK 
 
Definition 
Traditionally, PAS has been considered to be due to an abnormal insertion of the 
placenta, when the chorionic villi abnormally invade the myometrium (5). However, 
recent publications emphasize the non-invasive nature of placentation in PAS. The 
fundamental problem is the presence of an established myometrial defect in the uterus 
prior to pregnancy, clearly linked to previous surgical trauma, been history of cesarean 
section the main risk factor. When the placenta implants over that defect, as is the case 
of placenta previa in women with a history of cesarean section, abnormal migration of 
the placenta to deeper than usual planes in the uterine wall is possible (5). PAS is a 
severe complication of pregnancy associated with massive and life-threatening bleeding 
and has become one of the main causes of emergency hysterectomy (6). 
 
Traditional classification 
 
PAS has traditionally been classified based on the degree of penetration of the placenta 
into the myometrium (7). Therefore, only through the analysis of the post-hysterectomy 
uterus it’s possible to know where the patient was classified into. Due of the limitations 
of the histology-based approach of the traditional classification, some clinical criteria 
have been included, obtained during the laparotomy, proposed by FIGO (7). Something 
similar has been previously described by Collins et al (8). Those findings are not 
necessarily related to surgical difficulty and expected bleeding volume. Some authors 
indicate that those kinds of findings can be observed even in the absence of PAS since 
they are present in cases of uterine dehiscence with placenta previa (9). 
 
 
Table 1. General classification of PAS (FIGO) 
 
Grade 1 
Abnormally 
Adhered 
Placenta  
Clinical criteria 
Vaginal delivery 
● There is no separation with synthetic oxytocin and 
controlled cord traction. 

 
5 
 
 
(Adherent placenta 
or accreta). 
● Attempts of manual removal of the placenta result in 
profuse bleeding from the site of placental 
implantation, requiring mechanical maneuvers or 
surgical procedures. 
If laparotomy is required (even for cesarean delivery) 
● Same as above. 
● Macroscopically, the uterus shows no obvious 
distention over the placental bed ("placental 
protrusion"), no placental tissue invading the surface 
of the uterus, 
and 
nonexistent 
or minimal 
neovascularization. 
Histological criteria 
● Microscopic examinations of placental bed samples 
from a hysterectomy specimen shows wide areas of 
absent decidua between the villous tissue and the 
myometrium, with placental villi attached directly to 
the superficial myometrium. 
● The diagnosis cannot be made with freshly harvested 
placental tissue or random biopsies of the placental 
bed. 
Grade 2 
Abnormally 
invasive placenta 
(Increta). 
Clinical criteria 
At laparotomy 
● Abnormal gross findings on the placental bed: 
bluish/purple 
coloration, 
distension 
(placental 
"lump"). 
● Significant amounts of hypervascularization (dense 
vessels bed, convoluted vessels or multiple vessels 
running parallel and cephalocaudal along the uterine 
serosa). 
● No placental tissue is observed invading the uterine 
serosa. 
● Gentle cord traction causes the uterus to pull inward 
and there is no placental separation (the so-called 
dimple sign). 
Histological criteria. 

 
6 
 
 
 
● Uterine sample from hysterectomy or partial myometrial 
resection of the inccreta area showing placental villi 
within the muscle fibers, and sometimes in the lumen of 
the deep uterine vasculature (radial or arcuate arteries). 
Grade 3 
Abnormally 
invasive placenta 
(Percreta). 
Grade 3a: Limited to the uterine serosa 
Clinical Criteria 
In laparotomy 
● Abnormal gross findings on the uterine serosal surface 
(as noted above) and placental tissue has invaded the 
surface of the uterus. 
● No invasion of any other organ, the posterior wall of the 
bladder included (a clear surgical plane can be identified 
between the bladder and the uterus). 
Histological criteria 
● Uterine specimen from hysterectomy, showing villous 
tissue within or perforating the uterine serosa. 
Grade 3b: Invasion of the bladder  
Clinical Criteria 
In laparotomy 
● Placental villi are observed invade the bladder, but not 
other organs. 
● No clear surgical plane can be identified between the 
bladder and the uterus. 
Histological criteria 
● Uterine specimen from hysterectomy showing villous 
tissue perforating the uterine serosa and invading the 
bladder wall or the urothelium. 
Grade 3c: Invasion of other pelvic organs or tissues 
Clinical Criteria 
In laparotomy 
● Placental villi are found invading the broad ligament, 
the vaginal wall, the pelvic lateral wall  

 
 
 
 
 
or any other pelvic organ (with or without invasion 
of the bladder). 
Histological criteria 
● Uterine specimen from hysterectomy showing villous 
tissue perforating the uterine serosa and invading 
pelvic organs or tissues (with or without bladder 
invasion). 
For the purposes of this classification, "uterus" includes the 
uterine body and cervix. 
 
 
In addition to the difficulties associated with the traditional classification, it does not 
provide an ideal route on how to manage each case. The management options for PAS are 
multiple (10,11), without concretely defining which strategy is superior to others. It is 
common for a hospital and its PAS expert group to choose one type of treatment option 
and specialize in it, applying it in almost all their cases despite the variability of clinical 
presentations of PAS. For example, some protocols include embolization before or after 
fetal extraction (12), others apply total (13) or subtotal (14) hysterectomy in all cases, and 
others prefer expectant management, leaving the placenta in situ and waiting for its 
expulsion or resorption after a few weeks (15). 
The undiscriminated application of a specific procedure, exposes patients with less severe 
forms of PAS to the complications of that procedure (16), probably without gaining any 
additional benefit since they could have been managed with simpler interventions (2). 
Vascular management procedures (endovascular balloons, retroperitoneal dissection for 
aortic or internal iliac vessel clamping) have risks (17). Even total abdominal 
hysterectomy is associated with early ovarian failure and irreversible loss of fertility, 
along with psychological consequences for patients (18). Furthermore, it has been 
repeatedly demonstrated that hysterectomy is associated with greater blood loss, a higher 
rate of maternal complications and increased admission to intensive care for catastrophic 
bleeding (>2500 ml) compared to uterine sparing surgery (19).

 
8 
 
 
Topographic classification 
 
Due to the situation with the traditional classification, an interesting proposal rises, which 
is the topographic classification created by Palacios - Jaraquemada et al (1). This 
classification considers which uterine wall is affected (anterior, posterior or lateral), in 
addition to the level of involvement of the uterus (above or below the vesicouterine 
peritoneal fold) (4). 
It also includes knowledge of uterine irrigation and changes in pelvic anatomy when PAS 
is present, making it clear that lesions that occupy the lower part of the uterus, cervix or 
parametrium, known as sector 2 of uterine vascularization (1,20), present greater surgical 
difficulty. In this location, in addition to a complex anastomotic arterial network (vesical, 
vaginal, and cervical arteries, among others), there is proximity to urinary, nervous and 
vascular structures. Considering all the aforementioned conditions, the intraoperative 
findings define the category in which the patient is classified and recommendations for 
surgical management are established (table 2) (4). 
Table 2. Topographic classification of Placenta Accreta Spectrum (21) 
 
Type of 
PAS 
Arterial pedicles 
Vascular 
procedures 
Proposed 
treatment 
0 
UA 
None 
OSCS 
1 
UA, SVA 
NFV 
dissection/ligation 
OSCS 
2 
2U 
Upper 
(Upper) 
ObtA, 
IIA 
collaterals, UA, 
UretV 
NFV 
dissection/ligation 
OSCS 
2L 
Low 
(Lower) 
IIA collaterals, 
CA, VA, UretV 
IRAA, bilateral CIA 
Total 
hysterectomy 
3 
SVA, IVA, UA, CA, VA, VA 
NFV 
dissection/ligature 
IRAA, bilateral CIA 
OSCS vs 
Total 
hysterectomy 

 
9 
 
 
4 
SVA, IVA, UA, CA, VA, VA 
IRAA, bilateral CIA 
MSTH 
5 
5U 
Upper 
(Upper) 
UA, OA, 
collateral flow 
from IMA, IMA
 
fr
om IMA 
UA ligation 
OSCS 
5L 
Low 
(Lower) 
UA, 
ARA 
collaterals 
IRAA 
Total 
hysterectomy 
Intraoperative staging makes it possible to determine which uterine wall is affected and 
the relationship of the lesion to the vesicouterine peritoneal fold (above or below that 
level), as well as the predominance of neovascularization or the presence of 
vesicouterine fibrosis. 
In each topography, arterial pedicles are identified that provide most of the irrigation 
to the PAS area and determine the recommended vascular procedures and the type of 
treatment required (One Step Conservative Surgery [OSCS], Total Hysterectomy or 
Modified Subtotal Hysterectomy [MSTH]). 
PAS type 0: uterine "window" or dehiscence. PAS type 1: involvement of the upper 
part of the uterine segment. PAS type 2: parametrial involvement (2A: upper 
parametrial involvement, 2B: lower parametrial involvement). PAS type 3: 
involvement of the cervix or lower uterine segment (below the peritoneal reflex). PAS 
type 4: PAS type 3 plus vesicouterine fibrosis. PAS type 5: Involvement of the posterior 
uterine wall (5A: Involvement of the upper part of the posterior uterine wall. 5B: 
Lesions below the level of the peritoneal reflexion). 
AU: Uterine artery. SVA: Superior vesical artery. NFV: Neo-forming vessels. ObtA: 
obturator artery. IIA: internal iliac artery. UretV: ureteral vessels. CA: cervical artery. 
VA: vaginal arteries. IVA: inferior vesical artery. OA: ovarian artery. IMA: inferior 
mesenteric artery. ARA: anterior rectal artery. IRAA: infrarenal aortic artery. ICA: 
common iliac artery 
Another key factor is that a significant percentage of the hospitals responsible for the 
management of PAS do not have extensive experience in the management of the disease, 
and there are very few centers with a high flow of cases per year (22,23). Many of the 
hospitals do not have all the technological resources recommended by the so-called 
“centers of excellence” in PAS, nor do they have teams dedicated solely to the 
management of this disease ("PAS teams") (24,25). Those hospitals face difficulties in 

 
10 
 
 
choosing which type of treatment to offer each PAS patient who consults. Thus, it is 
common for most hospitals organizing their PAS team for the first time, to decide to offer 
hysterectomy to all their patients, even in cases with prenatal diagnostic uncertainty. 
Many groups even choose to apply vascular interventions to all of their PAS patients, 
even if such interventions ultimately prove to be excessive for the type of lesion found 
during surgery. 
This is worrisome, as 22% of the cases taken to hysterectomy for PAS do not end up 
having the diagnosis (26). This has become more relevant since it has been reported that 
most patients with PAS present with "mild" forms of the disease due to "superficial" 
penetration of the placenta into the uterine wall (13) or involvement of the upper part of 
the uterus, known as vascular sector 1 (1). All that without mentioning how when 
evaluating the perceptions of patients treated for PAS, they express how important it 
would have been to have options other than hysterectomy and to know that there was the 
possibility of preserving fertility in selected cases (27). 
In centers using the PAS topographic classification and individualized surgical 
management according to the severity of the lesion, up to 80% of cases can be managed 
with uterine-sparing surgery without increasing the volume of blood loss (1). The PAS 
topographic classification has been used in retrospective studies in low- and middle-
income countries (1,4) that correlates with clinical outcomes that justifies specific surgical 
interventions in selected cases. For example, it has been found that type 1 classification, 
which is the most frequent, is associated with less bleeding and a higher uterine 
preservation rate; while the types that include low parametrial invasion and invasion of 
the bladder trigone do not exceed 10% of cases and are linked to increased bleeding and 
higher surgical challenges (1). 
It should be noted that the available literature describing the relationship between 
topographic classification and its correlation with clinical outcomes is scarce, so it is 
considered essential to evaluate this classification in a prospective multicentric study that 
assesses its validity and correlation to surgical difficulty and

 
11 
 
 
clinical outcomes, which could determine the usefulness of the classification in the 
clinical setting. 
 
JUSTIFICATION FOR THE STUDY 
 
This research aims to evaluate the usefulness of the topographic classification of PAS. 
Although the classification is based on intraoperative findings and recognizes the 
particularities within each case of PAS, which has shown correlation to surgical difficulty 
and the effectiveness of one or another treatment option. To date there are no prospective 
multicentric studies that deepen and provide further strength to the above associations. In 
addition, the ease of its application and the acceptability of its use by the obstetrician-
gynecologists physicians who use it, is yet unknown. 
 
The topographic classification recognizes the pelvic anatomy and specially the arterial 
pedicles that irrigate each part of the uterus. It can be applied before incising the uterus 
and causing bleeding, enables a smooth decision-making process to choose the most 
appropriate surgical technique for each case, as well as the need for specific vascular 
interventions. Confirming its usefulness in different countries will facilitate its use by 
interdisciplinary teams dedicated to the management of PAS at the international level. 
 
RESEARCH QUESTION 
 
Is the topographic classification of placenta accreta spectrum useful in determining 
possible clinical outcomes? How acceptable it is by obstetrician-gynecologists who 
manage PAS? 
 
RESEARCH HYPOTHESES 
 
The topographic classification of placenta accreta spectrum is useful in determining 
possible clinical outcomes. The topographic classification has high acceptability among 
obstetrician-gynecologists who manage PAS.

 
12 
 
 
OBJECTIVES 
 
● General 
 
To evaluate the clinical outcomes of patients with a diagnosis of placenta accreta 
spectrum according to the topographic classification, and to explore the 
acceptability of this classification among obstetrician-gynecologists at the 
participating medical centers. 
● Specific 
 
1. To describe the demographic and clinical characteristics of patients with a 
diagnosis of placenta accreta spectrum. 
2. To analyze the clinical outcomes of patients diagnosed with placenta accreta 
spectrum according to the topographic classification. 
3. To explore the acceptability of the topographic classification for placenta 
accreta spectrum among obstetrician-gynecologists at the participating medical 
centers. 
 
EXPECTED RESULTS 
 
The aim of this study is to describe the demographic and clinical characteristics of patients 
with a diagnosis of placenta accreta spectrum, and to determine the correlation between 
the topographic classification and the clinical outcomes found in the study. Finally, to 
evaluated whether the proposed classification is accepted by the obstetrician-
gynecologists of the participating centers that manage placenta accreta spectrum patients. 
 
METHODOLOGY 
Design: 
 
1. Multicentric study of a prospective cohort. 
It is clarified that this is an observational study, in which data will be obtained 
from the medical records and other documents in each participating center, which 
are considered to be of routine use in day-to-day clinical practice. The study of 
the outcomes proposed in this protocol will be limited to those recorded in the 
clinical records and will be taken into account until the participant is discharged 

 
13 
 
from the hospital, during which a surgical intervention was performed due to the 
suspicion or diagnosis of PAS. 
Study population: 
 
1. Pregnant patients with a diagnosis of placenta accreta spectrum who visits any of 
the participating medical centers. 
2. Obstetrician-gynecologists working in participating medical centers. 
 
Participating centers: 
 
1. Academic General Hospital. Dr. Soetomo. Universitas Airlangga. Indonesia. 
2. Hospital Bertha Calderón Roque. Managua, Nicaragua. 
3. Instituto Nacional Materno Perinatal. Lima, Peru. 
4. Hospital General de Mexico. Dr. Eduardo Liceaga. CDMX, Mexico. 
5. Hospital de la Mujer. Dr. Percy Boland Rodríguez. Santa Cruz de la Sierra, 
Bolivia. 
6. Fundación Valle de Lili. Cali, Colombia. 
 
 
Criteria for the participation of the medical centers: 
 
The centers invited to participate are hospitals or clinics that already have knowledge in 
how to apply the surgical staging of PAS, and the topographic classification and have 
experience using it. 
● Level I and II hospitals, which are referral centers for the management of patients 
with placenta accreta. 
● Centers that handle more than 6 cases of placenta accreta per year. 
● To have interdisciplinary groups dedicated to the management of placenta accreta. 
● Have surgical management training on the various techniques recommended by 
the topographic classification. 
● Skilled to perform OSCS (One Step Conservative Surgery), Modified Subtotal 
Hysterectomy (MSTH) and Total Hysterectomy procedures.

 
14 
 
 
Patient admission criteria: 
 
It is projected that the period of patient enrollment will last 2 years, counting on from 
the first participant included. 
● Inclusion criteria: 
 
- 
Pregnant woman over 18 years old. 
- 
Prenatal diagnosis by ultrasound or MRI of PAS, regardless of the suspected 
degree of severity of the disease. 
- 
Case requiring surgical management, either as scheduled or emergent 
procedure. 
- 
Application of the topographic classification of placenta accreta spectrum 
during laparotomy. 
● Exclusion criteria: 
 
- 
None. 
 
 
Sample size and sampling strategy 
 
Due the anatomical classification of the placenta accreta spectrum proposed in this 
protocol is a strategy scarcely addressed in clinical studies, at the time of writing down 
this document, there is no information on outcomes associated with this classification that 
would directly allow the calculation of the sample, taking into account the seven options 
provided within the classification. Therefore, it will be determined by means of the only 
available study of this classification that addresses clinical complications, which 
considers 4 types: T1) upper bladder, T2) parametrium, T3) low bladder and T4) low 
bladder + fibrosis. (1) It is appropriate to take the total percentage of complications for 
each type indicated in the article, as shown below. 
 
T1 
n = 248 
T2 
n = 44 
T3 
n = 23 
T4 
N = 11 

 
15 
 
 
Total 
Complications 
 
31.05% 
 
50% 
 
95.65% 
 
100% 
 
 
The sample size was calculated using the openepi web tool, available at: 
https://www.openepi.com/Menu/OE_Menu.htm. To approximate to a round number the 
sample calculation, it was used the Cohorts option, considering the unexposed group as 
the classification option with the lowest percentage of total complications (T1), and the 
exposed group as the classification option with the highest percentage of total 
complications (T4). With a confidence level of 95%, power of 80%, ratio of 
unexposed/exposed =1, percentage of unexposed positives = 31.05% and percentage of 
exposed positives = 99.99%; the following results are obtained. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
It is expected that as we progress through the 7 option types of the proposed classification, 
we will have fewer patients; this implies that the classification with the lowest recruitment 
expectation will be T5b. All logistic efforts and recruitment strategies will be made to 
obtain at least 9 patients in the least frequent option type, considering the Fleiss sample 
size on continuous adjustment. Due to the difficulty of obtaining a significant and similar 
number of patients on each option type, it is considered appropriate to include all cases 
of PAS who visit the participating centers and meet the admission criteria in the 2-year 
period, with the possibility of extension, if the minimum number of cases for each option 

 
16 
 
type is not achieved. 
 
Data collection techniques 
 
The group of obstetrician-gynecologists will inform the principal investigator or study 
coordinator about patients that can be included in the study. Once it is confirmed that they 
meet the inclusion criteria, the data will be collected from the electronic or paper-based 
medical records of the hospital, protecting the identity of the patients at all times. 
Once the collection of patient data has been completed, the survey to evaluate the 
acceptability of the topographic classification of PAS will be administered to the group 
of obstetricians who manage placenta accreta at the participating centers. Each 
participating physician who has applied the topographic classification to the patients 
treated during the study period, will complete the survey only once at the end of the study 
period. 
This information will be typed and stored in the RedCap platform. At Fundación Valle 
del Lili, the task will be performed by the research assistants’ that are part of the principal 
investigators team, and in the participating hospitals by delegates designated by each 
center. The extraction and collection of data will be supervised by the principal 
investigator, with prior authorization from the ethics committee. 
For the quality analysis, 10% of the data will be randomly sampled and compared with 
the medical records or paper-based documents. If there is discordance between the data, 
another 10% will be randomly analyzed and if there is still discordance, the entire 
database will be revised. This task will be the responsibility of each participating center, 
in relation to the number of patients admitted by them. 
 
Data Management and Statistical Analysis 
 
Specific Objective 1: To describe the sociodemographic and clinical characteristics 
of patients with a diagnosis of placenta accreta spectrum.

 
17 
 
 
Descriptive Analysis: Stratification by subgroups will be performed according to the 
topographic classification of PAS, as follows: T1, T2a, T2b, T3, T4, T5a and T5b. 
Qualitative variables will be summarized as percentages and presented as absolute 
frequencies. For quantitative variables, the normality distribution will be determined by 
means of the Kolmogorov Smirnov statistic (sample size greater than 50 patients is 
foreseen), where a result of p value >0.05 would comply with the assumption of 
normality. For variables with normal distribution, mean and standard deviation will be 
determined; and for variables without normal distribution, median and interquartile 
ranges (Q1 - Q3) will be indicated. 
Inferential Analysis: For quantitative variables, a statistical test of the difference 
between the means of the 7 subgroups (independent groups) will be performed by means 
of one-way ANOVA for independent groups. If the variable does not have a normal 
distribution, the Kruskall-Wallis test will be performed. 
In both cases, the null hypothesis (H0) indicates that the mean or median numbers of the 
7 subpopulations are equal; the alternate hypothesis (Ha) refers to the above being 
different. If the p-value indicated by those tests is ≥ 0.05 (5%), it can be stated that there 
are no statistically significant differences between the mean or median numbers of the 7 
subpopulations, with 95% confidence, which is set for the study. If the p-value is < 0.05, 
the hypothesis of having no difference in the mean or median numbers (H0) is rejected. 
That does not imply that a particular subgroup is superior or inferior to another. 
For qualitative variables, a statistical test of the difference in proportions of the 7 
subgroups (independent groups) will be performed by means of the Chi-square test. A 
result with a p-value ≥ 0.05 (5%) can be interpreted as: the proportions of the variable in 
question do not differ, in terms of statistical significance, among the seven groups. In case 
the p-value is < 0.05 indicates that there are statistically significant differences between 
at least two of the seven groups with respect to the proportions of the variable addressed. 
This does not imply that a particular subgroup is superior or inferior to another. 
The results are shown in Table 3. 
 
 
 
 
 

 
18 
 
Specific Objective 2: To analyze the clinical outcomes of patients diagnosed with 
placenta accreta spectrum according to anatomical classification. 
Descriptive Analysis: Stratification by subgroups will be performed according to the 
anatomical classification of PAD as follows: T1, T2a, T2b, T3, T4, T5a and T5b. 
Qualitative variables will be summarized as percentages and presented as absolute 
frequencies. For quantitative variables, the normality distribution will be determined by 
means of the Kolmogorov statistic. 
 
Smirnov (sample size greater than 50 patients is expected), where a result of p-value 
>0.05 would comply with the assumption of normality. For variables with normal 
distribution, mean and standard deviation will be determined; and for variables without 
normal distribution, median and interquartile ranges (Q1 - Q3) will be indicated. 
Inferential Analysis: For quantitative variables, a statistical test of the difference in 
means of the 7 subgroups (independent groups) will be performed by means of one-way 
ANOVA for independent groups. If the variable does not have a normal distribution, the 
Kruskall-Wallis test will be performed. 
In both cases, the null hypothesis (H0) indicates that the means or medians of the 7 
subpopulations are equal; the alternate hypothesis (Ha) refers to the above being different. 
If the p-value indicated by these tests is ≥ 0.05 (5%), it can be stated that there are no 
statistically significant differences between the means or medians of the 7 subpopulations, 
with 95% confidence, which is set for the investigation. If the p-value is < 0.05, the 
hypothesis of equality of population means or medians (H0) is rejected. This does not 
imply that a particular subgroup is superior or inferior to another. 
For qualitative variables, a statistical test of the difference in proportions of the 7 
subgroups (independent groups) will be performed by means of the Chi-square test. A 
result with a p-value ≥ 0.05 (5%) can be interpreted as: the proportions of the variable in 
question do not differ in terms of statistical significance, among the seven groups. In case 
the p-value is < 0.05, it indicates that there are statistically significant differences between 
at least two of the seven groups with respect to the proportions of the variable been 
assessed. That does not imply that a particular subgroup is superior or inferior to another. 
The results are shown in Table 4. 
 
Specific Objective 3: To explore the acceptability of the topographic classification of 

 
19 
 
placenta accreta spectrum among obstetrician-gynecologists at the participating 
medical centers. 
In the scientific literature there is no validated scale to evaluate the acceptability of a new 
clinical classification, which in this case is proposed as a topographic classification of 
PAS. After an exhaustive search, it was concluded that the The Ottawa Acceptability of 
Decision Rules Instrument would be utilized, which is a widely used instrument to 
evaluate the acceptability of a norm among physicians. There is no linguistic adaptation 
to Spanish, so a direct translation of its content was made. 
After the principal investigator had reviewed it, was necessary make adaptations to some 
items, which were: 
a) Change the original term "norm" to "anatomical classification for PAS". In all 
items. 
b) The following item is added: The application of the anatomical classification for 
PAS generates an additional consumption of resources. It is considered important 
to ask about that consideration, taking into account that the proposed classification 
will be very useful in low- and middle-income countries with limited healthcare 
systems. 
c) Item withdrawn: The evidence supporting the norm is flawed, as there are not 
enough studies addressing the present classification; therefore, it is not relevant to 
include the item. 
d) The following item is removed: I am already following another norm or similar 
strategy, since this proposed classification has no point of comparison with other 
types of classifications used in the day-to-day clinical practice. 
Descriptive Analysis: Descriptive analysis will be performed using absolute frequencies 
and calculated percentages of the response option for each item. Finally, the absolute 
frequencies of each response option will be added up and the response percentage will be 
calculated to find the global acceptability of the anatomical classification of the placenta 
accreta spectrum, in relation to what was addressed in the survey. 
The results are presented in Table 5. 
 
Table of Variables 
 

 
20 
 
Variable 
Name 
Definition 
Type of 
variabl
e 
Operation
al Level 
Measure 
Summary 
Objectiv
e that 
resolves 
1. 
Identifier 
number in 
the study 
Unique 
consecutive 
number 
that 
identifies 
the 
participant in the 
study 
Quantitative 
Round 
numbers 
starting 
from 1 
NA 
NA 
2. 
Date of 
surgery 
for PAS 
treatme
nt 
dd/mm/yyyy 
on 
which 
surgical 
management 
is 
performed for the 
treatment 
of 
placental accretism 
NA 
dd/mm/yy 
NA 
NA 
3. 
Maternal age 
Time in years, from 
the 
participant's 
date of birth to the 
date of visit, due to 
suspicion 
or 
diagnosis of PAS 
Quantitative 
Numbers 
greater 
≥18 
Central 
tendency and 
dispersion 
1 
4. 
Gravity 
Number 
of 
pregnancies 
the 
patient has had at 
the time of the first 
visit for suspected 
or diagnosed PAS. 
(Considering 
the 
current pregnancy) 
Quantitative 
Number 
Central 
tendency and 
dispersion 
1 
5. 
Parity 
Number 
of 
previous deliveries 
of the patient at the 
first 
consultation 
for suspected or 
diagnosed PAS. 
Quantitative 
Number 
Central 
tendency and 
dispersion 
1 
6. 
Previous 
Cesarean-
sections 
Number of previous 
cesarean 
sections 
the patient has had 
until the first visit 
for suspected or 
confirmed 
diagnosis of PAS 
 
Quantitative 
 
Number 
 
Central 
tendency and 
dispersion 
 
1 
7. 
Placenta 
previa in the 
current 
pregnancy 
Isthere 
placenta 
previa 
(total/partial/low 
lying) in the current 
pregnancy? 
 
Qualitative 
Nominal 
 
0: No1: Yes 
Central 
tendency and 
dispersion 
1 
8. 
Prenatal 
diagnostic 
method 
of 
PAS 
Diagnostic 
imaging 
study by which PAS is 
diagnosed 
 
Qualitative 
Nominal 
 
1: Ultrasound 
2: 
Magnetic 
Resonance 
Imaging 
3: Ultrasound 
and Magnetic 
Resonance 
Imaging 
4: PAS prenatal 
diagnosis not 
available 
Absolute 
frequency 
and 
percentage 
1 

 
21 
 
(intraoperativ
e diagnosis of 
PAS) 
 
9. 
Gestational 
age at the 
time 
of 
delivery 
Weeks of gestation 
at time of delivery of 
the 
current 
pregnancy 
 
Quantitative 
 
Number 
 
Central 
tendency and 
dispersion 
1 
10. Topographic 
classificatio
n (Palacios-
Jaraquemad
a) 
Classification into 7 
groups as described 
in Annex 1 
 
Qualitative 
Ordinal 
 
1: Type 1 
2: Type 2U 
3: Type 2L 
4: Type 3 
5: Type 4 
6: Type 5U 
7: Type 5L 
 
Frequencies 
and 
percentages 
1 
11. Days 
of 
postoperativ
e 
hospitalizati
on 
Number of days the 
patient 
was 
hospitalized from the 
day of surgery to the 
day of discharge. 
Quantitative 
 
Number 
Central 
tendency and 
dispersion 
 
1 
12. Surgical 
time 
Time 
in 
minutes 
between skin incision 
to skin closure 
Quantitative 
 
Number 
Central 
tendency and 
dispersion 
 
1 

 
22 
 

 
23 
 
 
CLINICAL OUTCOME VARIABLES 
13. Type of 
surgery 
Type of surgical 
priority 
Qualitative 
Nominal 
0: Programmed  
1: Emergent 
Frequencies and 
percentages 
2 
14. Interventi
on 
performed 
 
Treatment 
option used 
Qualitative 
Nominal 
0: Total hysterectomy 
1: Modified subtotal 
hysterectomy 
 2: One step conservative 
surgery 
3. Other 
Frequencies and 
percentages 
2 
15. Criteria 
on how 
to select 
surgical 
techniqu
e 
Criteria for the 
selection of the 
type of 
intervention 
applied as 
management 
Qualitative 
Nominal 
1: Surgical technique chosen 
based on the topographic 
classification 
2: Surgical technique chosen 
without the topographic 
classification  
 
Frequencies and 
percentages 
2 
16. Volume of 
intraopera
tive blood 
loss 
Blood volume 
lost during 
surgery 
measured  
in (ml) 
Quantitative 
Number 
Central 
tendency 
and 
dispersion 
2 
17. Usage of 
vascular 
interventi
ons 
What type of 
vascular 
intervention 
was used 
during the 
surgery 
Qualitative 
Nominal 
1: None 
2: Ligation of internal iliac 
arteries 
3: Endovascular occlusion of 
internal iliac or common iliac 
arteries (balloons) 
4: Clamping or ligation of the 
aorta 
5: Aortic Endovascular 
Occlusion (Balloon) 
6: Manual aortic compression 
7.Other 
Frequencies and 
percentages 
2 

 
24 
 
 
18. Bladder injury 
Did the patient end up 
with bladder injury 
due to the surgery for 
PAS? 
Qualitative 
Nominal 
0: No 
1: Yes 
Frequencies and 
percentages 
2 
19. Ureteral injury 
Did the patient end up 
with ureteral injury 
during the surgery for 
PAS? 
Qualitative 
Nominal 
0: No 
1: Yes 
Frequencies and 
percentages 
2 
20. Surgical 
reintervention  
Does the patient need 
surgical 
reintervention? 
Qualitative 
Nominal 
0: No 
1: Yes 
Frequencies and 
percentages 
2 
21. Complications 
associated with
vascular 
interventions 
The patient presented 
thrombosis or other 
complication during 
post-surgery associated 
with vascular 
interventions. 
Qualitative 
Nominal 
0: No 
1: Yes 
Frequencies and 
percentages 
2 
22. Post-
operative 
ileus 
Did the patient 
present ileus during 
postoperative 
period? 
Qualitative 
Nominal 
0: No 
1: Yes 
Frequencies and 
percentages 
2 
23. Supra-
fascial 
hematoma 
Did the patient present 
with supra-fascial 
hematoma post-
surgery? 
Qualitative 
Nominal 
0: No 
1: Yes 
Frequencies and 
percentages 
2 
24. Maternal 
death  
Does the patient die during 
this study? 
Qualitative 
Nominal 
0: No 
1: Yes 
Frequencies and 
percentages 
2 
25. Clavien 
Dindo 
Classification 
of 
complication
s 
Classification of 
complications that 
occurred during this 
study according to the 
Clavien Dindo scale as 
shown in Annex 3 
Qualitative 
ordinal 
1. None 
2. Grade I 
3. Grade II 
4. Grade IIIa 
5. Grade IIIb 
6. Grade IVa  
7. Grade IVb  
8. Grade V 
Frequencies and 
percentages 
2 

 
25 
 
 
Blank Tables 
 
Table 3. Clinical characteristics of patients with a diagnosis of placenta accreta spectrum 
stratified by the topographic classification. 
 
 
Feature 
Topographic 
Classification 
T1 
n 
T2U 
n 
T2L 
n 
T3 
n 
T4 
n 
T5U 
n 
T5L 
n 
Maternal 
Age 
Mean 
or 
media
n (SD 
or 
IQR) 
Mean 
or 
media
n (SD 
or 
IQR) 
Mean 
or 
media
n (SD 
or 
IQR) 
Mean 
or 
media
n (SD 
or 
IQR) 
Mean 
or 
media
n (SD 
or 
IQR) 
Mean 
or 
media
n (SD 
or 
IQR) 
Mean 
or 
media
n (SD 
or 
IQR) 
Gravity 
Mean 
or 
media
n (SD 
or 
IQR) 
Mean 
or 
media
n (SD 
or 
IQR) 
Mean 
or 
media
n (SD 
or 
IQR) 
Mean 
or 
media
n (SD 
or 
IQR) 
Mean 
or 
media
n (SD 
or 
IQR) 
Mean 
or 
media
n (SD 
or 
IQR) 
Mean 
or 
media
n (SD 
or 
IQR) 
Parity 
Mean 
or 
media
n (SD 
or 
IQR) 
Mean 
or 
media
n (SD 
or 
IQR) 
Mean 
or 
media
n (SD 
or 
IQR) 
Mean 
or 
media
n (SD 
or 
IQR) 
Mean 
or 
media
n (SD 
or 
IQR) 
Mean 
or 
media
n (SD 
or 
IQR) 
Mean 
or 
media
n (SD 
or 
IQR) 
Previous 
cesareans  
Yes No 
 
n (%) 
n (%) 
 
n (%) 
n (%) 
 
n (%) 
n (%) 
 
n (%) 
n (%) 
 
n (%) 
n (%) 
 
n (%) 
n (%) 
 
n (%) 
n (%) 
Placenta previa 
in the current 
pregnancy 
Yes 
No 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
Trimester of 
gestation at the 
time of 
diagnosis of 
PAS  
First trimester 
(≤12) 
Second quarter 
(from 13 to 28) 
Third 
trimester 
(>29) 
 
 
n (%) 
 
n (%) 
 
n (%) 
 
 
n (%) 
 
n (%) 
 
    n (%) 
 
 
n (%) 
 
n (%) 
 
n (%) 
 
 
n (%) 
 
n (%) 
 
n (%) 
 
 
n (%) 
 
n (%) 
 
n (%) 
 
 
n (%) 
 
n (%) 
 
n (%) 
 
 
n (%) 
 
n (%) 
 
n (%) 

 
26 
 
Prenatal 
diagnostic 
method of 
PAS 
 
Ultrasound 
Magnetic 
Resonance 
Ultrasound 
and magnetic 
resonance 
PAS prenatal 
diagnosis not 
available 
(intraoperative 
diagnosis of 
PAS) 
 
 
 
n (%) 
n (%) 
 
n (%) 
 
 
 
n (%) 
 
 
 
 
n (%) 
n (%) 
 
n (%) 
 
 
 
n (%) 
 
 
 
 
n (%) 
n (%) 
 
n (%) 
 
 
 
n (%) 
 
 
 
 
n (%) 
n (%) 
 
n (%) 
 
 
 
n (%) 
 
 
 
 
n (%) 
n (%) 
 
n (%) 
 
 
 
n (%) 
 
 
 
 
n (%) 
n (%) 
 
n (%) 
 
 
 
n (%) 
 
 
 
 
n (%) 
n (%) 
 
n (%) 
 
 
 
n (%) 
 

 
27 
 
 
Gestational age at 
delivery 
Mean or 
median 
(SD or 
IQR) 
Mean or 
median 
(SD or 
IQR) 
Mean or 
median 
(SD or 
IQR) 
Mean or 
median 
(SD or 
IQR) 
Mean or 
median 
(SD or 
IQR) 
Mean or 
median 
(SD or 
IQR) 
Mean or 
median 
(SD or 
IQR) 
 
 
Table 4. Surgical and clinical outcomes of patients with a diagnosis of placenta accreta 
spectrum according to an anatomical classification. 
 
Clinical 
Outcome 
Topographic 
Classification 
T1 
n 
T2U 
n 
T2L 
n 
T3 
n 
T4 
n 
T5U 
n 
T5L 
n 
p-value 
Type of 
surgery 
Scheduled 
Emergency 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
Type of 
procedure 
Total 
hysterectomy 
Subtotal 
hysterectomy 
Surgery 
one-step 
conservative 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
Vascular 
intervention 
None 
Ligation of 
internal iliac 
arteries 
Endovascular 
occlusion of 
internal iliac 
or common 
iliac arteries 
(balloons) 
Clamping or 
ligation of 
aorta 
Endovascular 
aortic 
occlusion 
(Balloon) 
Manual aortic 
compression 
Another 
 
 
n (%) 
n (%) 
 
 
n (%) 
 
 
 
 
n (%) 
n (%) 
 
 
n (%) 
 
n (%) 
 
 
n (%) 
n (%) 
 
 
    n (%) 
 
 
 
 
n (%) 
 
 
n (%) 
 
 
n (%) 
 
n (%) 
 
 
n (%) 
n (%) 
 
 
     n (%) 
 
 
 
 
n (%) 
 
 
 
n (%) 
 
 
n (%) 
 
n (%) 
 
 
n (%) 
n (%) 
 
 
n (%) 
 
 
 
 
n (%) 
 
 
 
n (%) 
 
 
   n (%) 
 
  n (%) 
 
 
n (%) 
n (%) 
 
 
n (%) 
 
 
 
 
n (%) 
 
 
 
n (%) 
 
 
   n (%) 
 
   n (%) 
 
 
n (%) 
n (%) 
 
 
n (%) 
 
 
 
 
n (%) 
 
 
 
n (%) 
 
 
   n (%) 
 
  n (%) 
 
 
n (%) 
n (%) 
 
 
n (%) 
 
 
 
 
n (%) 
 
 
 
n (%) 
 
 
   n (%) 
 
  n (%) 

 
28 
 
 
 
 
 
 
 
 
 

 
29 
 
 
Stage of 
Hemorrhage  
Stage 1 
Stage 2 
Stage 3 
Stage 4 
Stage 5 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
Bladder Injury 
No 
Yes 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
Ureteral 
Injury 
No 
Yes 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
Arterial 
Thrombosis 
No 
Yes 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
Post-
operative 
ileus 
 No 
Yes 
 
n (%) 
n (%) 
 
n (%) 
n (%) 
 
n (%) 
n (%) 
 
n (%) 
n (%) 
 
n (%) 
n (%) 
 
n (%) 
n (%) 
 
n (%) 
n (%) 
Supra-fascial 
hematoma  
No 
Yes 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
Surgical 
reintervention 
No 
Yes 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
Maternal 
death 
 No 
Yes 
 
n (%) 
n (%) 
 
n (%) 
n (%) 
 
n (%) 
n (%) 
 
n (%) 
n (%) 
 
n (%) 
n (%) 
 
n (%) 
n (%) 
 
n (%) 
n (%) 
Classification of 
complications 
Grade I 
Grade II 
Grade IIIa 
Grade IIIb 
Grade Iva 
Grade IVb 
Grade V 
 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 

 
30 
 
 
 
Table 5. Acceptability of the anatomical classification for placenta accreta spectrum 
among obstetrician-gynecologists from the participating medical centers (N). 
 
Statements 
Strongly 
disagree 
Moderately 
disagree 
Slightly 
Disagree 
Slightly 
agree 
Moderately 
agree 
Totally 
agree 
No 
opinion/ 
Don't 
know 
The anatomical classification 
for PAS is easy to use. 
n 
(%) 
n 
(%) 
n (%) 
n (%) 
n 
(%) 
n (%) 
n (%) 
The anatomical classification 
for PAS is easy to remember. 
n 
(%) 
n 
(%) 
n (%) 
n (%) 
n 
(%) 
n (%) 
n (%) 
The anatomical classification 
for PAS is useful to me. 
n 
(%) 
n 
(%) 
n (%) 
n (%) 
n 
(%) 
n (%) 
n (%) 
The anatomical classification 
for PAS is clear and 
unambiguous. 
n 
(%) 
n 
(%) 
n (%) 
n (%) 
n 
(%) 
n (%) 
n (%) 
My colleagues would support 
the use of anatomical 
classification for PAS. 
n 
(%) 
n 
(%) 
n (%) 
n (%) 
n 
(%) 
n (%) 
n (%) 
Patients would benefit from 
the use of anatomical 
classification for PAS. 
n 
(%) 
n 
(%) 
n (%) 
n (%) 
n 
(%) 
n (%) 
n (%) 
The use of anatomical 
classification for PAS would 
result in a better use of 
resources. 
n 
(%) 
n 
(%) 
n (%) 
n (%) 
n 
(%) 
n (%) 
n (%) 
  The use of anatomical 
classification for PAS would 
increase the likelihood of 
lawsuits 
 
n 
(%) 
n 
(%) 
n (%) 
n (%) 
n 
(%) 
n (%) 
n (%) 

 
31 
 
 
The anatomical 
classification for 
PAS does not take 
into account an 
important clinical 
detail 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
The environment in 
which I work makes 
it difficult to use the 
anatomical 
classification for 
PAS. 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
The application of 
topographic 
classification 
generates additional 
resource 
consumption. 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
TOTAL 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
n (%) 
 
 
OPERATIONAL ASPECTS 
 
The invited hospitals are institutions that already applying the proposed classification or 
that were previously trained to implement this classification, in addition to the surgical 
techniques that might be required in each case. Prior to this study, some health centers 
were trained by the principal investigator of this study via telemedicine (28). Likewise, 
the topographic classification of PAS been proposed (Annex 1) will be socialized and 
reinforced to the obstetrician-gynecologists who manage patients with placenta accreta 
spectrum, aiming to achieve a correct and standardized classification in all the 
participating centers, which reduces measurement bias. Prospective data collection will 
start from the moment the medical history is taken from the institutional database of each 
participating center, considering the qualitative and quantitative variables of the chosen 
population, that are related to the surgical intervention and the clinical outcomes during 
the postoperative period. In this case, the immediate postoperative period will be followed 
up until the time of discharge. All the information obtained will be typed and saved in the 
RedCaP platform, to have traceability of the information and ensure the confidentiality of 
the patient’s data is maintain all the time. 
The participating hospitals will make the necessary arrangements at the local level for the 

 
32 
 
execution of the study, sign a confidentiality agreement that states they are collaborating 
on this study with Fundación Valle de Lili. It will be the responsibility of each 
participating center to comply with local and international regulations on good clinical 
practices in research and the stipulations stated by the ethics committee. 
Once the collection of patient data has been completed, a survey will be carried out to 
evaluate the acceptability of the topographic classification by the group of obstetrician-
gynecologists who manage placenta accreta patients in each participating hospital. Given 
that for this last objective, the calm environment of those being evaluated could be 
disrupted by requesting their participation, prior to starting the survey, authorization will 
be requested for the use of the participants' data, their authorization being understood as 
affirmative if they choose “I accept” in the statement that provides that information, prior 
to the beginning of the questionnaire and their refusal if they do not choose to accept 
and/or do not complete the survey. 
Subsequently, the methodology advisor and the statistical team will perform the analysis 
according to the tables of variables and blank tables proposed display the patients’ 
characteristics and the results of the study. Once the above process has been completed, 
the manuscript will be written. 
 
SOCIALIZATION OF RESULTS 
 
The manuscript resulting from this study will be published in a journal indexed in Web 
of Science and/or SCOPUS; in addition, the results will be presented at congresses and 
other academic events related to the subject and the area of Obstetrics & Gynecology. 
The expected audience is obstetrician-gynecologists, as well as personnel in training in 
health areas, such as resident physicians and/or undergraduate students. 
 
ETHICAL CONSIDERATIONS 
 
The present study adheres to the Helsinki declaration and the 2016 CIOMS guidelines. 
All the investigators have successfully completed and passed the Good Clinical Practice 
(GCP) course, which is designed to prepare research personnel on how to conduct clinical 
trials with human participants. 
Researchers agree to comply with the principles and responsibilities defined in the 2010 
Singapore Declaration on Integrity in Research. All investigators state that they are aware 

 
33 
 
of the four principles of bioethics such as: autonomy, recognizing that all patients are 
capable of deliberating about their personal goals and acting on the decisions they can 
make. Patients with limited autonomy are entitled to protection. Beneficence, as the moral 
obligation to act in the welfare of others. Non-maleficence, which is understood as doing 
no harm and preventing harm. And justice, acting in an ethical and equitable manner. 
● 
Risk Level (According to Resolution 8430) 
 
Given that this prospective research study only intends to classify patients with prenatal 
diagnosis of placenta accreta spectrum according to diagnostic images and intraoperative 
findings, in addition to describing clinical outcomes without intervening in the treatment 
decision-making process; nor it is contemplated to conduct surveys with conflicting 
questions of moral conduct, it is considered a research with minimal risk according to 
article 11 of resolution 8430 of 1993 of the Republic of Colombia, which classifies studies 
into 4 groups, the current study belonging to group B: "B. Research with minimal risk: 
These are prospective studies that employ the recording of data through common 
procedures consisting of: physical or psychological diagnostic examinations or routine 
treatments, among which are considered: weighing the subject, electrocardiograms, 
hearing tests, thermographs, collection of feces and external secretions, obtaining 
placenta during delivery, collection of amniotic fluid upon rupture of membranes, 
obtaining saliva, decidual teeth and permanent teeth extracted for therapeutic indication, 
dental plaque and calculi removed by non-invasive prophylactic procedures, hair and 
nail clipping without causing disfigurement, blood collection by venous puncture in 
adults in good health, with a maximum frequency of twice a week and a maximum volume 
of 450 ml in two months except during pregnancy, moderate exercise in healthy 
volunteers, psychological tests to groups or individuals in which the subject's behavior 
will not be manipulated, investigation with medications of common use, wide therapeutic 
margin and registered in this Ministry or its delegated authority, using the indications, 
doses and routes of administration established, and which are not medications that are 
found in article 55 of this resolution". 
However, given that this is a prospective study where the peace of mind of those being 
evaluated could be disturbed by requesting their participation, prior to applying the first 
questionnaire to the participating obstetrician-gynecologists, in each case, authorization 
from the participants will be requested. At the beginning of the surveys there will be a 
section where they will have to select the option "I accept" to continue filling out of the 

 
34 
 
forms. Once the participant accepts, they will be able to continue filling out the survey; if 
the participant does not accept, the surveys will be made not available to be completed 
(Annex 2). 
 
● Request for waiver of informed consent 
 
As mentioned above, this study will only use data from the medical records of the 
participants and will not carry out any type of intervention nor will it imply changes in 
the clinical behavior or prognosis of the patients admitted, for which reason an exception 
to the informed consent will be requested from the ethics committee of Fundación Valle 
del Lili. 
 
● Risk-control strategies 
 
One of the potential risks of this study is the identification of the participating patients, 
therefore, we are committed to maintaining strict confidentiality and will not publish 
images or anything that confirms patients are participanting. In order to guarantee this, 
the patients will be hidden by means of numerical codes; furthermore, no person outside 
the research or the ethics committee will have access to the data. We declare that we are 
aware of and comply with the 1995 declaration of 1999 that regulates the use medical 
records in Colombia. 
 
● Conflict of interest 
 
The researchers state that there are no conflicts of interest. This research has no direct 
impact on natural or environmental resources. 
 
● Author 
 
The products of the proposed project will comply with the institutional rules of 
authorship, which in turn will be aligned with the recommendations of the ICMJE.

 
35 
 
SCHEDULE 
 
Activity/ Year/ 
Name of month 
202 
2 
Oct 
202 
2 
Nov 
202 
2 
Dec 
202 
3 
Jan 
202 
3 
Feb 
202 
4 
Jan 
202 
4 
Feb 
202 
4 
Mar 
202 
4 
Apr 
202 
4 
May 
1.Writing the 
protocol 
x 
x 
Approvals 
2. Socializing the 
protocol 
x 
3. Methodology 
Evaluation 
x 
4. Ethics 
committee 
evaluation 
x 
x 
Execution 
5. Collecting of the 
information 
x 
x 
6. Analysis of the 
data 
x 
Socialization of Results and Reports 
7. Writing the 
paper 
x 
8. Poster 
presentation (if 
aplicable) 
x 
9. Article 
Submission 
x 
10. Reporting to 
Ethics Committee  
x 
11. (Annual - 
Renewal) 

 
36 
 
 
 
REFERENCES 
 
1. 
Palacios-Jaraquemada JM, Fiorillo A, Hamer J, Martínez M, Bruno C. Placenta 
accreta spectrum: a hysterectomy can be prevented in almost 80% of cases using 
a resective-reconstructive technique. Journal of Maternal-Fetal and Neonatal 
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39 
 
ANNEXES 
 
Annex 1. Topographic Classification of Placenta Accreta Spectrum. 
Intraoperative staging makes it possible to determine which uterine wall is affected and the relationship 
of the lesion to the vesicouterine peritoneal fold (above or below that level), as well as the predominance 
of neovascularization or the presence of vesicouterine fibrosis. 
In each topography, some arterial pedicles are identified that provide most of the irrigation to the PAS 
area and that determine the recommended vascular procedures and the type of treatment necessary (One 
Step Conservative Surgery [OSCS], Total hysterectomy or Modified SubTotal Hysterectomy [MSTH]) 
Type 0 PAS: uterine “window” or dehiscense. Type 1 PAS: uterine segment upper part involvement. 
Type 2 PAS: parametrial involvement (2U: upper parametrial involvement, 2L: lower parametrial 
involvement). Type 3 PAS: cérvix or uterine segment lower part involvement (below the peritoneal 
reflection). Type 4 PAS: type 3 PAS plus vesicouterine fibrosis. Type 5 PAS: uterine posterior wall 
involvement (5U: involvement of the upper part of that wall. 5L: Lesions below the level of the 
peritoneal reflection) 
UA: uterine artery. SVA: superior vesical artery. NFV: Newly formed vessels. ObtA: obturator artery. 
IIA: internal iliac artery. UretV: Ureteral vessels. CA: cervical artery. VA: vaginal arteries. IVA: inferior 
vesical artery. OA: ovarian artery. IMA: inferior mesenteric artery. ARA: anterior rectal artery. IRAA: 
infrarenal aortic artery. CIA: common iliac artery 
 

 
40 
 
 
 
Annex 2. Validated Ottawa Acceptability Assessment Survey 
 
Indicate your level of agreement with each of the following statements in reference to the 
anatomical classification for PAD 
DATA USE AUTHORIZATION PARAGRAPH: 
 
This questionnaire is intended to collect information that will be used only for research 
purposes, your data will be handled only by the research team in charge of Fundación 
Valle del Lili (Cali - Colombia), respecting your confidentiality. Therefore, if you agree 
with the information presented and wish to participate in the study, please select "I 
agree", fill in your name and proceed with the questionnaire, otherwise, you can close 
this window and not continue with the survey. 
Please fill in your full name: 
 
 
 
 
 
 
Annex 3. Clavien Dindo classification of the severity of surgical complications.