(887) Perinatal outcomes of Small-for-Gestational-Age (SGA) newborns to mothers with and without a Müllerian anomaly

Müllerian anomalies contribute to a distinct uterine environment which influence fetal development and have implications for both fetal growth and obstetrical outcomes. The current study aimed to compare the immediate perinatal outcomes of SGA newborns after development in a uterus with a Müllerian anomaly to SGA newborns who developed in a normal uterus.

Study Design:

A retrospective population-based cohort study was conducted including all SGA infants born between 1991 and 2021 in a tertiary medical center. The delivery data were collected from the institutional computerized database. Multiple gestations and chromosomal abnormalities were excluded. The study group included SGA newborns from uterus with a Müllerian anomaly compared to a group of SGA newborns from a normal uterus. Maternal characteristics and immediate perinatal outcomes were evaluated. Multiple logistic regression models were used for statistical analysis.

Results:

During the study period, 16,210 SGA neonates delivered in our medical center; 0.61% (n = 99) were born to mothers with Müllerian anomalies and 99.39% (n=16,111) were born to mothers with a normal uterus. Müllerian anomalies were related to higher rates of cesarean delivery (OR 20.4; 95% CI [12.3-33.7]; p < .001), preterm delivery < 37 weeks (OR 4.3; 95% CI [2.7-6.7]; p < .001), preterm delivery< 34 weeks (OR  4.1; 95% CI [2.2-7.7]; p < .001) and very low birth weight (< 1500g) (OR  3.5; 95% CI [1.9-6.3]; p < .001). However, perinatal outcomes, such as Apgar score < 7 at 5 minute and pH < 7 were comparable between the study groups.

Conclusion:

Offspring with SGA that developed in a uterus with a Müllerian anomaly have a higher risk of cesarean delivery, preterm delivery and very low birth weight compared to SGA offspring developed in a normal uterus. However, there were no significant differences regarding adverse perinatal outcomes between the study groups.