Impact of pre-labour second twin presentation on early neonatal outcomes in vaginal twin delivery

Objective Aim of this study is to assess early neonatal outcomes of second twins after vaginal birth of the first twin and verify whether second twin in non-cephalic presentation is safe to undergo vaginal delivery. Materials and methods This is a retrospective cohort study of women who had vaginal delivery of the first twin in a regional public obstetric unit in Hong Kong, from 1 January 2012 to 31 December 2022. Early neonatal outcomes, twin-to-twin delivery interval and rates of second twin Caesarean section were evaluated. Results A total of 197 pairs of twins are included and grouped by pre-labour presentation of the second twin, with 119 cephalic (60.4%), 47 breech (23.9%), and 31 transverse (15.7%). Adverse early neonatal outcomes are rare, and no significant differences were found between the groups in terms of low Apgar score, cord blood pH below 7.2 or 7.1, NICU admission and birth trauma. There is a statistically significant difference in twin-to-twin delivery interval across the 3 groups (P = 0.005), with post-hoc analysis showing difference between cephalic and breech groups only. Internal podalic version was performed in 30 cases for transverse lie or high head in the second stage with high successful rate (86.7%). The rate of combined delivery is low (1.5%) and does not differ among the 3 groups. Conclusion Pre-labour presentation of the second twin does not affect its early neonatal outcomes and does not influence the rate of combined vaginal-Caesarean delivery if birth attendants skilled in performing IPV are available.