Factors influencing the mode of delivery and associated pregnancy outcomes for twins: a retrospective cohort study in a public hospital.

OBJECTIVES To determine current trends for different modes of delivery in twin pregnancies, factors affecting the mode of delivery, and associated outcomes. DESIGN Retrospective cohort study. SETTING A public hospital in Hong Kong. PARTICIPANTS All twin pregnancies booked at Kwong Wah Hospital during a 3-year period from 1 April 2006 to 31 March 2009. RESULTS Of 197 sets of twins, 35 (18%) were delivered vaginally and 162 (82%) by caesarean section (47% were emergencies and 53% elective). In all, 32 (37%) of the elective and 21 (28%) of the emergency caesarean sections were in response to maternal requests. Vaginal delivery was more common in mothers with a history of vaginal delivery and monochorionic diamniotic twins. Women who conceived by assisted reproduction or those who had a tertiary education were more likely to deliver by caesarean section. The type of conception and the presentation of the second twin were statistically significant factors affecting maternal choice on the mode of delivery. Maternal age did not affect the choice of delivery mode. Except for the higher frequency of sepsis and cord blood acidosis in second twins delivered vaginally, there were no significant differences in neonatal morbidity between the groups that attempted vaginal delivery or requested caesarean sections. All the women who had compression sutures or hysterectomy to control massive postpartum haemorrhage were delivered by caesarean section. CONCLUSION A high caesarean section rate observed in our cohort was associated with maternal requests for this mode of delivery. The type of conception and the presentation of the second twin were statistically significant factors affecting maternal choice on mode of delivery. Women's requests for caesarean delivery out of the concern for their babies are not supported by current evidence. In response to a woman with a twin pregnancy requesting caesarean delivery, the pros and cons of vaginal deliveries and caesarean sections should be fully explained before the woman's autonomy is respected.