P-288 How do pregnancy complications, intrapartum, and neonatal risks differ in bicornuate and didelphys uteri. A population-based study
Authors: Alharazi S , Dahan M , Badeghiesh A , Baghlaf H 
Published: July 2024

Abstract

Study question
Are there differences between didelphys and bicornuate uteri regarding obstetrical and neonatal outcomes based on an analysis of a population database?

Summary answer
Didelphys uteri present higher risks of preeclampsia, preterm delivery, PPROM, and cesarean delivery; while bicornuate uteri present higher risks of placenta previa, and placental abruption.

What is known already
Didelphys and bicornuate uteri are similar congenital anomalies with duplication of the uterine corpus. It is thought that both defects are similar when it comes to pregnancy complications, with increased risks of preterm delivery (PTD), malpresentation, and cesarean delivery, when compared to women without uterine anomalies. The didelphys uterus has two cervixes and a double vagina while the bicornuate uterus has one cervix and a single vagina. This minor difference may or may not alter the risks of pregnancy complications in these groups. However, obstetric and perinatal outcomes for didelphys and bicornuate uteri have never been directly compared.

Study design, size, duration
This retrospective population-based cohort study utilized data from the Healthcare-Cost and Utilization Project-Nationwide Inpatient Sample (HCUP-NIS) from 2010 to 2014, inclusively. There were 3,846,342 births between 2010 and 2014, 1146 women with didelphys uteri and 6327 women with bicornuate uteri were included in the database and the study. Women were included only once per pregnancy.

Participants/materials, setting, methods
HCUP-NIS is the largest inpatient database in the USA and is comprised of hospitalizations throughout the USA. It provides information relating to seven-million inpatient stays yearly, includes 20% of admissions, and represents over 96% of Americans. Multivariate logistic regression was conducted to explore associations between bicornuate uteri and delivery outcomes while controlling for confounding effects. According to the Tri-Council Policy Statement (2018), IRB approval was not required, given data was anonymous and publicly available.

Main results and the role of chance
No significant difference was seen between the groups in regard to age, income, medical insurance plan, rates of obesity, illicit drug use, chronic hypertension, diabetes, thyroid disease, HIV, tobacco smoking during pregnancy, previous cesareans, pregnancy from IVF, and multiple gestations (P &gt; 0.05). The only difference was in racial distribution, which was controlled for in the subsequent analysis (p &lt; 0.05).In comparison to pregnant women with bicornuate uteri, patients with didelphys uteri were more likely to experience preeclampsia (aOR 1.38 95%CI: 1.05-1.80 P = 0.020), preterm premature rupture of membranes (PPROM) (aOR 1.76 95%CI1.32-2.34 P = 0.000), preterm delivery (aOR 1.39 95% CI1.18-1.64P=0.000), and higher chances of cesarean delivery (aOR 1.41 95% CI1.20-1.64 P = 0.000), after controlling for confounding demographics. Additionally, women with didelphys uteri have less risks of developing placenta previa (aOR 0.26 95%CI: 0.08-0.84 P = 0.024) and Abruptio placenta (aOR 0.52 95%CI 0.31-0.87 P = 0.013). No significant difference was seen between the groups regarding pregnancy induced hypertension, eclampsia, gestational diabetes, chorioamnionitis, operative vaginal delivery, hysterectomy, post-partum hemorrhage, wound complications, blood transfusion, maternal death, maternal infection, venous thromboembolism, pulmonary embolism or DIC (P &gt; 0.05). Moreover, there was no significant difference between the two groups when comparing neonatal outcomes, including small for gestational age fetuses and intrauterine fetal demise (P &gt; 0.05).

Limitations, reasons for caution
The limitation of our study are related to its retrospective nature and use of administrative database, which relies on the accuracy, and consistency of the individual coding the data, and the masking of undetected bias.

Wider implications of the findings
The present study demonstrates that women with bicornuate and didelphys uteri have certain differences when it comes to pregnancy, and intrapartum complications, including rates of preeclampsia, placenta previa, placental abruption, cesarean section, PPROM, and preterm delivery. These findings emphasize the importance of individualized perinatal care in these two cases.

Trial registration number
not applicable