Second twin presentation change linked to combined delivery

A retrospective study published in the Archives of Gynecology and Obstetrics has identified specific intrapartum factors associated with combined twin delivery, a procedure defined as the vaginal delivery of the first twin followed by a cesarean delivery of the second. The research, led by Roy Zigron and colleagues, evaluated clinical and intrapartum variables stratified by the presentation of the second twin to determine which conditions are most strongly linked to this mixed mode of delivery. The study focused on twin pregnancies where the first twin was in a vertex position and was delivered vaginally, providing a focused look at the complexities of managing twin births in a specific clinical context.

The investigation was a 13-year retrospective study that included 754 women with twin pregnancies meeting the inclusion criteria. Of these, 565 had vertex–vertex pregnancies and 189 had vertex–nonvertex pregnancies. The researchers stratified the pregnancies based on the presentation of the second twin before the delivery of the first twin to allow for a more nuanced analysis of the factors influencing the delivery method for the second twin.

Combined delivery occurred in 4.2% of the vertex–vertex group, corresponding to 24 out of 565 pregnancies, and in 9.0% of the vertex–nonvertex group, corresponding to 17 out of 189 pregnancies. The difference in the frequency of combined delivery between these two groups was statistically significant, with a p-value of 0.016. This finding underscores the importance of the second twin’s presentation in determining the likelihood of a mixed delivery approach, highlighting that the risk is not uniform across all twin gestations.

In the vertex–vertex group, the researchers used conventional multivariable logistic regression to analyze the data. They found that an intrapartum presentation change of the second twin was significantly associated with combined delivery. The adjusted odds ratio for this association was 5.12, with a 95% confidence interval ranging from 1.97 to 13.30. This suggests that if the second twin changes its position during labor in a vertex–vertex pregnancy, the likelihood of requiring a cesarean section for the second twin increases substantially.

Further analysis within the vertex–vertex group revealed that several maternal and obstetric factors were associated with the presentation change of the second twin. Maternal age of 35 years or older was associated with an adjusted odds ratio of 1.98, with a 95% confidence interval of 1.01 to 3.91. Multiparity was associated with an adjusted odds ratio of 4.52, with a 95% confidence interval of 1.54 to 13.24. Additionally, induction of labor was associated with an adjusted odds ratio of 3.14, with a 95% confidence interval of 1.64 to 6.01.

For the vertex–nonvertex group, the researchers employed Firth penalized logistic regression due to the small number of outcome events and evidence of separation in the data. In this model, the absence of epidural analgesia remained associated with combined delivery. The adjusted odds ratio was 4.45, with a 95% confidence interval of 1.51 to 14.41, after adjusting for gestational age less than 32 weeks and intertwin birthweight discordance of 20% or more.

The study’s conclusion emphasizes that the associations with combined delivery are predominantly intrapartum rather than antepartum. The presentation change of the second twin is described as an immediate intrapartum event rather than a predictor that can be identified before labor begins. This distinction is crucial for clinical practice, as it suggests that the findings are most relevant to intrapartum preparedness rather than antenatal risk prediction.

The study’s design and statistical methods were tailored to the specific challenges of analyzing twin deliveries, with the use of Firth penalized logistic regression addressing the issue of small sample sizes in the vertex–nonvertex group.

Overall, the research contributes to the understanding of the factors that influence the mode of delivery for the second twin in twin gestations.

Subject of Research: Clinical factors associated with combined delivery in twin gestations

Article Title: Clinical factors associated with combined delivery in twin gestations according to the presentation of the second twin

Article References: Zigron, R., Lessans, N., Porat, S., Sompolinsky, Y., & Rottenstreich, A. (2026). Clinical factors associated with combined delivery in twin gestations according to the presentation of the second twin. Archives of Gynecology and Obstetrics. https://doi.org/10.1007/s00404-026-08595-w

Image Credits: AI Generated

DOI: 10.1007/s00404-026-08595-w

Keywords: twin pregnancy, combined delivery, cesarean section, vaginal delivery, intrapartum factors, fetal presentation, obstetrics, retrospective study, Clinical, factors, associated, combined