O-228 Do myomectomies decrease third trimester pregnancy complications when compared to women without myomectomies and uterine fibroids in situ? A study of an American population database
Authors: Ginod P , Badeghiesh A , Baghlaf H , Dahan M  H 
Published: July 2024

Abstract

Study question
Myomectomies are performed to decrease pregnancy complications, among other indications, however, do myomectomies decrease third trimester pregnancy complications?

Summary answer
Post-myomectomy, pregnancies experienced more complications including hypertensive disorders, premature-pre-term-rupture of membranes, preterm-delivery, placenta-previa, cesareans, uterine ruptures, wound complications, transfusions, and small for gestational age infants.

What is known already
Patients with fibroid uterus experience reduced fertility rates and increased in obstetrical complications compared to patients without fibroids. If the removal of fibroids improves fertility is controversial for intramural fibroids, it is recommended for submucosal fibroids by the American College Of Gynaecology guidelines.
It is a common, untested belief that myomectomies may reduce the risks of certain obstetrics complications. While rates of mal-placentation and hypertensive disorders may increase post-myomectomy as shown by the literature comparing myomectomy vs. control groups without fibroids, other complications may be anticipated to decrease. However, no population-based studies have attempted to answer this question.

Study design, size, duration
Retrospective cohort study, using the Healthcare Cost and Utilization Project Nationwide Inpatient Sample between 2004 and 2014, inclusively, based on International Classification of Diseases, 9th edition, diagnoses (ICD-9). Data collected from 48 states and the District of Columbia, representing 20% of annual hospital admissions in the United States.
Population-based study, including 89,025 with uterine fibroids: 7508 pregnancies with previous abdominal myomectomy (AM) or laparoscopic myomectomy (LM), and 81,517 controls with uterine fibroids in-situ, without myomectomies.

Participants/materials, setting, methods
We included patients delivery discharge diagnoses or maternal deaths, and with either uterine fibroids (ICD-9 codes 218.0, 218.1, 218.2, 218.9) or AM or LM prior to the pregnancy, (ICD-9 codes 68.29 and 68.19 or CPT procedure code 58140, 58145, 58146, 58545 and 58546).
Binomial logistic regression was used and adjusted for age, race, income quartiles, smoking, previous cesarean section, chronic and pregnancy-induced hypertension, obesity, multiple gestations, pre-gestational and gestational diabetes mellitus.

Main results and the role of chance
The myomectomy group was characterized by older patients, higher rates of Caucasian race, chronic hypertension, previous cesarean delivery, and multiple gestations, and lower, income quartiles, rates of obesity, compared to the fibroid in-situ group (P &lt; 0.05). There was no difference for rates of medical insurance plan type, tobacco smoking, pregestational diabetes, illicit drug use, thyroid disease, or in vitro fertilization use (P &gt; 0.05, all).
The myomectomy group had increased rates of pregnancy-induced hypertension (adjusted odd ratios(aOR)-1.15, 95% confidence intervals(CI):1.06-1.26), preeclampsia (aOR:1.25 95%CI:1.12-1.41), preterm delivery (aOR:1.4, 95%CI:1.27-1.53), preterm premature rupture of membranes (aOR:1.29, 95%CI:1.05-1.58), placenta previa (aOR:1.59, 95%CI:1.32-1.92), cesarean delivery (aOR:37.1, 95%CI:27.35-50.4), uterine rupture (aOR:2.1, 95%CI:1.06-4.16), blood transfusion (aOR:1.21, 95%CI:1.68-2.24), wound complications (aOR:1.44, 95%CI:1.1-1.9), disseminated intravascular coagulation (aOR:1.58, 95%CI:1.1-2.27), and small for gestational age (SGA) infants (aOR:0,19, 95%CI:1.05-1.39) compared to the fibroid in-situ group.
The myomectomy group had a lower rate of gestational diabetes mellitus (aOR:0,88, 95%CI:0,79-0,97), chorioamnionitis (aOR:0,74, 95%CI:0,6-0,93), maternal infection (aOR:0.79, 95%CI:0.65-0.95), spontaneous (aOR:0.03, 95%CI:0.02-0.04) and operative vaginal delivery (aOR:0.87, 95%CI:0.75-0.99), and postpartum hemorrhage (aOR:0.73, 95%CI:0.62-0.87).
There was no significant differences for rates of gestational hypertension, eclampsia, preeclampsia or eclampsia superimposed on pre-existing hypertension, abruptio placenta, hysterectomy, maternal death, deep venous thrombosis, pulmonary embolism and venous thromboembolism events (P &gt; 0.05, all).

Limitations, reasons for caution
The retrospective nature of the study may mask undetected bias. Moreover, although the rate of uterine rupture was increased in the myomectomy group, it was rare and requires confirmation. Further prospective studies are needed to evaluate the outcomes in pregnancy after myomectomy.

Wider implications of the findings
The complications seen after myomectomies were likely related to uterine-incisions and alteration of myometrial vascularization, impairing trophectoderm invasion and leading to hypertensive disorders, mal-placentation, and abnormalities of fetal growth. Patients should be counselled regarding these potential risks. Increased understanding of the role of myomectomies on reproductive outcomes needs further study.

Trial registration number
not applicable