The investigators conducted this prospective study in women with twins pregnancy planned for trial of vaginal delivery and gave birth between January 2014 and December 2019, in the Department of obstetrics and Gynaecology of the Sabah Maternity Hospital, Sabah Specialized Area, Kuwait. The Sabah Maternity Hospital is a tertiary care hospital for the country of Kuwait with approximately 12500 deliveries per year. The study protocol was approved by the Ethics Committee.
Over an 8-year period, 124 twin pregnancies at gestational age ≥32 weeks with both twins presenting as a vertex and eligible for vaginal delivery were reviewed. Excluded were patients with the following intrapartum factors which may affect mode of delivery of second twin: 1. Presentation of the 2nd twin: breech or other than vertex; 2. Monochorionic twins; 3. Induction of labour; 4. difference in foetal weight between twin B and twin A ≥25%. The chi-square statistic was used to compare differences in the incidence of retained second twin between the groups.