2.1. Study design and setting
The results of twin pregnancy cases followed and delivered between January 2013 and December 2015 at Health Sciences University, Gazi Yasargil Research and Training Hospital, were obtained retrospectively from the hospital’s automation system records. Obstetric ultrasound was performed on all women involved in this study, with verbal consent, and the results were compared with the last menstrual period and first trimester obstetric ultrasound to determine the gestational week and chorionicity. The presentations and estimated fetal weights of the twins were determined via prenatal obstetric ultrasound. Out of all twin pregnancies, women who desire VB with the first twin in vertex presentation that were undergoing VB were included in group 1. Women who do not want VB with the first twin in vertex presentation that were undergoing a primary ‘elective’ CB for the first time were included in group 2 and VB has not been attempted for this patient group.
The primary outcome was early neonatal mortality and secondary outcomes related to maternal and perinatal clinical characteristics were analysed between the groups. The groups were compared in terms of maternal age, gravida, parity, body mass index (BMI), assisted reproductive technology (ART), term birth rates (≥37 weeks 0 days) and preterm birth rates (<37 weeks, divided into two groups: between 32 weeks 0 days and 33 weeks 6 days and between 34 weeks 0 days and 36 weeks 6 days), type of birth (infant 1 and 2), birth weight, five-minute activity–pulse–grimace–appearance–respiration (APGAR) score, five-minute APGAR less than 7, trauma-associated morbidity (was identified as spinal cord injury, fracture of skull, humerus, femur or clavicle, brachial plexus injuries, facial nerve injuries, subdural, subarachnoid and intracerebral hemorrhages), early neonatal mortality rate (ENMR: number of neonatal deaths in 0–7 days x 1000/total live births), maternal death and severe postpartum hemorrhage.
Experienced obstetricians evaluated all twin pregnancies that were accepted to the birth room after the start of spontaneous labor pains, and these pregnancies were continuously monitored during labor. The oxytocin regimen is the same as in singleton pregnancies. After the birth of the first twin, the presentation of the second twin was determined by ultrasound. For pregnancies with the second twin in vertex presentation, amniotomy was not performed before the head of the twin was engaged unless forceps or vacuum was required due to unsafe fetal condition. In the second twin with non-vertex presentation, the obstetrician decided the best birth method (spontaneous breech birth, assisted breech birth, external cephalic version, internal cephalic version, etc.) and implemented it following consultation with the pregnant woman. If the second twin is not in a cephalic presentation (eg, breech or transverse), our preference is breech extraction if there are no contraindications to this procedure. All twin VBs were performed by experienced obstetricians (13,14). The women for whom the obstetrician decided CB was needed for the second twin were taken to an operating room quickly, and the twin CB was performed. The hospital serves a wide area, and because of the high number of births, four operating rooms and an anaesthesia team are ready around the clock so CBs can be performed in these operating rooms without loss of time if necessary.