Data on breech deliveries at our hospital has been prospectively collected in a comprehensive ‘breech database’ since 2001 to the present (variables listed below). Maternal delivery data as well as neonatal mortality and morbidity data are registered in the data base. Information on maternal complications was extracted from medical charts and the Partus database in retrospect. Medical charts were also reviewed for all neonates transferred to the neonatal intensive care unit (NICU) in order to verify and validate information. All women with a singleton, term gestation (>37 weeks) breech presentation between 2001 and 2011 were included. Exclusion criteria were preterm deliveries (< 37 weeks), multiple pregnancies, antepartum death and major congenital malformations.
Mode of delivery
Breech deliveries were classified as planned vaginal breech deliveries if the woman delivered vaginally or by acute cesarean section after a previous decision of vaginal delivery, whether the decision was taken before labor or after a pelvimetry in early labor. Mode of planned delivery was recorded prospectively in the medical charts. Women with breech presentation were selected to vaginal delivery according to Norwegian guidelines (see below).
After spontaneous onset of labor, continuous electronic fetal monitoring was conducted in all cases with known breech presentation. In 2005, ST analyses of the fetal electrocardiogram (STAN) were introduced in breech deliveries. After spontaneous progress to umbilical level, the arms and the aftercoming head were actively delivered by the Lövsets and the Veit-Smellie-Moriceau maneuvers, respectively.
Norwegian national guidelines for vaginal delivery of breech infants
1) Gestational age ≥ 34 weeks, 2) Estimated birth weight ≥ 2000 g and ≤4000 g (individual assessment between 4000–4500 g), 3) Pelvimetry (x-ray) was optionally performed in nulliparous women, in women with previous complicated vaginal birth, or previous birth of infant < 3000 g. Sagittal inlet diameter more than 11.0 – 11.5 cm and sum of pelvic outlet diameter more than 31.5 – 32.5 cm were accepted measures for vaginal delivery, 4) Frank breech or complete breech presentation, 5) No serious obstetrical complications or serious maternal diseases, 6) Adequate institution size (preferably more than 400–500 births a year), 7) Mode of delivery and delivery assisted by, or supervised by experienced gynecologists 8) Adequate anesthesia: epidural, pudendal nerve block, and prompt access to regional anesthesia if necessary.
Neonatal outcome factors
Variables recorded in the breech database were: Apgar score <7 and <4 at 5 minutes, admission to NICU ≥ 4 days, brachial plexus injury, cephalhematoma, bone fracture, respiratory distress syndrome, mechanical ventilation treatment, continuous positive airway pressure (CPAP) treatment, and facial palsy. Gestational length was consistently based on ultrasound examination at 17–19 weeks, or if not available, the last menstrual period. Small for gestational age (SGA) was defined as having a birth weight lower than the 10th percentile calculated for the normal population based on data from Norwegian Birth Registry .
Maternal outcome factors
Maternal age, parity (para 0, para ≥ 1), gestational length, birth weight, x-ray pelvimetry, and indication for mode of delivery were extracted from the breech database. Maternal complications were not originally registered, and were extracted from medical charts and the Partus database in retrospect. These variables include episiotomy, anal sphincter rupture, blood loss (dichotomized to ≤ 1500 or >1500 ml), need for blood transfusion, deep venous thrombosis, postoperative hematoma, wound infection requiring antibiotics, endomyometritis, and febrile illness > 1 day.
The primary outcome measure was neonatal mortality or serious perinatal morbidity similar to the criteria of the TBT  (Admission to NICU ≥ 4 days, cephalohematoma, bone fracture, respiratory distress syndrome, mechanical ventilation treatment, continuous positive airway pressure (CPAP) treatment, Apgar < 4 after 5 minutes).
Data were described with proportions for categorical variables and with median and ranges for continuous variables. Crude associations between categorical data were assessed with chi-square tests and t-tests for continuous variables. Non-parametric tests were applied when appropriate. The associations between categorical variables were quantified as odds ratios (ORs) with 95% confidence intervals (95% CI). P-values <0.05 were considered statistically significant. Data were analysed using the Statistical Package for Social Sciences (SPSS version 18.0).
The study was considered as quality assurance by the regional Committee for Ethics in Medical Research, Region South (2011/1006 D), and did not require approval or written consent. The Norwegian data inspectorate (2011/28688) approved the study.