(897) Uterine synechiae and the risk of adverse pregnancy outcomes: a systematic review and meta-analysis

Uterine synechiae are frequently found during pregnancy. Evidence in regard to adverse

outcomes in pregnancy associated with this finding is conflicting. The aim of our study

was to systematically review the currently available evidence on the rate of adverse

outcomes in pregnancy with uterine synechiae.

Study Design:

PubMed, ScienceDirect, Cochrane Library, and CINAHL were reviewed from their

inception to July 2025. We included all studies comparing adverse outcomes in

pregnancy in patients with and without a uterine synechiae. Bias was evaluated using

the Newcastle-Ottawa Scale.

Results:

We identified 4 studies with 628 in the uterine synechiae group, and 65,959 in the

control. In patients with uterine synechiae, the risk of preterm delivery at less than 37

weeks (OR 1.80, 95%, CI 1.35, 2.39), preterm premature rupture of membranes (OR

3.58, 95%, CI 1.13, 11.36), placental abruption (OR 3.34, 95%, CI 1.57, 7.13), lower

birth weight (MD -154.29, 95%, CI -259.20, -49.38), and presence of placenta previa

(OR 3.19, 95%, CI 1.07, 9.57) were significantly increased as compared to the control

group. The risk of preterm birth at less than 34 weeks (OR 1.88, 95%, CI 0.92, 3.85),

cesarean section (OR 1.06, 95%, CI 0.51, 2.21), fetal growth restriction (OR 1.14, 95%,

CI 0.54, 2.44), stillbirth (OR 1.37, 95%, CI 0.50, 3.76), and NICU admission (OR 10.98,

95%, CI 0.29, 414.01) and were not significantly different in patients with uterine

synechiae as compared to the control group. Sub-group analysis for cesarean section

for fetal malpresentation was significantly higher in patients with uterine synechiae as

compared to those without (OR 1.97, 95%, CI 1.23, 3.13).

Conclusion:

The presence of uterine synechiae during pregnancy was associated with a significantly

increased risk of preterm birth at less than 37 weeks, preterm premature rupture of

membranes, placental abruption, decreased birth weight, presence of placenta previa,

gestational age of delivery and cesarean section for fetal malpresentation. These data

support an increased risk of adverse events in pregnancy in the setting of uterine

synechiae.