Poster Session 1
Category: Clinical Obstetrics
Poster Session 1
.jpg "Roie Alter, MD (he/him/his) photo")
Roie Alter, MD (he/him/his)
Hadassah Medical Center and Hebrew University of Jerusalem, Jerusalem, Israel
Jerusalem, Yerushalayim, Israel
Inbal Akavian, MD, MPH
Hadassah Ein-karem hospital, Obstetrics and gynecology department, Jerusalem
Jerusalem, Yerushalayim, Israel
Shlomo Yahalomy, MD
Department of Obstetrics and Gynecology, Hadassah Hebrew University Medical Center, Ein Kerem
Jerusalem, Yerushalayim, Israel
Joshua Isaac Rosenbloom, MD
Hadassah Medical Center and Hebrew University of Jerusalem, Jerusalem, Israel
Jerusalem, Yerushalayim, Israel
Aharon Tevet, MD
Department of Obstetrics and Gynecology, Hadassah Hebrew University Medical Center, Ein Kerem
Jerusalem, Yerushalayim, Israel
Hadar Rosen, MD
Hadassah Ein-karem hospital, Obstetrics and gynecology department, Jerusalem
Jerusalem, Yerushalayim, Israel
Vaginal delivery is a well-established and safe mode of birth for twin pregnancies under appropriate conditions. However, when the second twin is larger, concerns arise about technical difficulty, neonatal morbidity, and combined delivery. This study evaluates whether these concerns are supported by assessing cesarean rates and neonatal outcomes in larger twin B discordancy undergoing a trial of labor
Study Design:
This retrospective cohort study included all diamniotic twin deliveries ≥32 weeks with a cephalic first twin at a tertiary center from 1/2019 to 04/2025. Elective cesareans were excluded. Larger B Discordancy was defined as >20% weight difference with a larger second twin; concordant twins (–20% < D < 20%) were controls. The primary outcome was mode of delivery. Secondary outcomes included cesarean delivery for the second twin and 5-minute Apgar< 7
Results:
Among 1017 twin deliveries, 885(87.0%) were concordant and 53(5.2%) were discordant with a larger second twin. The distribution of vertex–non-vertex presentations was similar between groups (42.8 vs. 41.5%, p=.851). Vaginal delivery was common across all twins but more frequent in vertex–vertex compared to vertex–non-vertex pairs (77.9% vs. 69.5%, p =.003).
Cesarean delivery for both twins was more common in discordant pairs (34 vs. 22.3%, p=.049), yet cesarean delivery for the second twin alone remained rare and was not significantly different between groups (1.9 vs. 1.1%, p=.474). Similarly, 5-minute Apgar < 7 rates for both first and second twins were low and comparable (0 vs. 0.9% for Twin A; 0 vs. 1.4% for Twin B; both p=1).
In logistic regression, both discordancy (OR=1.84, p=.043) and non-vertex second twin (OR=1.47, p=.015) were independently associated with emergency cesarean
Conclusion:
Although discordant twins with a larger second twin had higher overall cesarean rates, this was likely due to events during labor and not delivery difficulty. The consistently low rates of second twin cesarean and reassuring neonatal outcomes support that vaginal delivery is a safe and viable option in well-selected discordant larger second twin