Strategies for Improving the Detection of Dysglycemia in the Postpartum Period in Women With Gestational Diabetes: Electronic Reminders and New Diagnostic Criteria
Phase: NA
Conditions: Gestational Diabetes Mellitus (GDM)
Sponsor: University of Sao Paulo General Hospital

Study Protocol with Statistical Analysis 
Plan and Informed Consent Form 
Official Study Title: Strategies to Improve Postpartum Screening for Dysglycemia in Women 
with Gestational Diabetes: Electronic Reminders and Alternative Diagnostic Criteria 
NCT Number: Pending 
Document Date: 2026-03-11 
Institution: Obstetrics Clinic – Hospital das Clínicas, University of São Paulo Medical School 
(HC‑FMUSP), São Paulo, Brazil 
Principal Investigator: Tatiana Assunção Zaccara, MD, PhD 
1. Background and Rationale 
Gestational diabetes mellitus (GDM) is a common complication of pregnancy and is 
associated with increased risk of developing prediabetes and type 2 diabetes after delivery. 
Clinical guidelines recommend that women with prior GDM undergo a 75‑g oral glucose 
tolerance test (OGTT) between 6 and 12 weeks postpartum to reclassify glycemic status. 
However, adherence to postpartum screening is frequently low. Reminder systems have 
shown potential to improve attendance. Additionally, emerging evidence suggests that the 
1‑hour glucose measurement during OGTT may be a more sensitive marker of dysglycemia 
than the traditional 2‑hour value. This study evaluates strategies to improve postpartum 
screening and compares two diagnostic approaches. 
2. Objectives 
Primary Objective: 
Evaluate strategies to improve postpartum screening for dysglycemia among women with 
prior gestational diabetes. 
Secondary Objectives: 
1. Assess the impact of WhatsApp reminder messages on attendance to the postpartum 
OGTT. 
2. Compare the prevalence of prediabetes and diabetes using two diagnostic strategies 
applied to the same OGTT. 
3. Identify risk factors associated with postpartum dysglycemia. 

3. Study Design 
The study includes two complementary analyses conducted at the Obstetrics Clinic of 
HC‑FMUSP. 
Analysis 1 – Randomized Clinical Trial 
Participants will be randomly allocated to a control group receiving standard care or an 
intervention group receiving WhatsApp reminders 7 and 3 days before the scheduled OGTT. 
If the participant does not attend, a follow‑up message offering rescheduling will be sent. 
Analysis 2 – Observational Diagnostic Comparison 
Participants will undergo a 75‑g OGTT with glucose measurements at fasting, 1 hour, and 2 
hours. Two diagnostic strategies will be applied: Strategy A (fasting and 2‑hour glucose) 
and Strategy B (fasting and 1‑hour glucose). Diagnostic disagreement will be evaluated. 
4. Eligibility Criteria 
Inclusion Criteria: 
- Diagnosis of gestational diabetes according to IADPSG criteria 
- Delivery at HC‑FMUSP 
- Scheduled OGTT between 6 and 12 weeks postpartum 
- Written informed consent 
Exclusion Criteria: 
- Withdrawal of consent 
- Incomplete OGTT due to vomiting (excluded from analysis 2 only) 
5. Outcomes 
The primary outcome is attendance to the postpartum OGTT. Secondary outcomes include 
prevalence of prediabetes and diabetes according to each diagnostic strategy and diagnostic 
discordance between criteria. 
6. Statistical Analysis Plan 
Data will be analyzed using SPSS and R software. Continuous variables will be described 
using means and standard deviations or medians and interquartile ranges. Categorical 
variables will be presented as frequencies and percentages. 
Comparisons between groups will use Student’s t‑test or Mann‑Whitney tests for 
continuous variables and Chi‑square or Fisher’s exact tests for categorical variables. 
Diagnostic discordance between strategies will be assessed using the McNemar test. 
Statistical significance will be defined as p < 0.05. 

7. Ethical Considerations 
The study follows the principles of the Declaration of Helsinki and Brazilian National Health 
Council Resolution 466/2012. Participation is voluntary and participants may withdraw at 
any time without affecting their medical care. The study protocol was approved by the 
institutional Research Ethics Committee. 
8. Informed Consent Form (English Version) 
You are invited to participate voluntarily in the research project “Strategies to Improve 
Postpartum Screening for Dysglycemia in Women with Gestational Diabetes: Electronic 
Reminders and Alternative Diagnostic Criteria.” The purpose of this study is to evaluate 
whether reminder messages improve attendance to the postpartum oral glucose tolerance 
test and to compare two diagnostic strategies for detecting metabolic abnormalities. 
If you agree to participate, you may receive reminder messages via WhatsApp before your 
scheduled test. Regardless of group allocation, all participants will undergo the standard 
75‑g oral glucose tolerance test between 6 and 12 weeks after delivery, with blood samples 
collected at fasting, 1 hour, and 2 hours. 
The study involves minimal risk. The only additional procedure compared to routine care is 
an extra blood sample collected 1 hour after glucose ingestion. All personal information will 
remain confidential. Your participation is voluntary and you may withdraw at any time 
without affecting your medical care. 
If you have questions about the study, you may contact the principal investigator: Dr. 
Tatiana Assunção Zaccara, Obstetrics Clinic – HC‑FMUSP, São Paulo, Brazil. 
Participant Name: ______________________________ 
Signature: ____________________________________ 
Date: ____ / ____ / ______