Perinatal outcome in births after a previous cesarean section at high trial of labor rates.

Introduction: Trial of labor (TOLAC) is an option in most preganancies after a cesarean section The objective of the study was to compare perinatal outcome in TOLAC and non-TOLAC deliveries in a population with high TOLAC rates.
Material and Methods: This was a cohort study based on population data from the Medical Birth Registry of Norway. We included term, cephalic, single, second deliveries, 1989-2009, after a first cesarean section (n = 43 422). TOLAC, TOLAC failure, non-TOLAC deliveries, and after high-risk and low-risk pregnancies (no risk/any risk), were compared with respect to offspring mortality, 5-minute Apgar score Apgar < 7 and < 4, transfer to a neonatal intensive care unit, and neonatal respiratory distress syndrome.
Results: Statistically significant differences were observed (P <0.05). In the low-risk group the offspring mortality was 2.3/1000 in TOLAC compared with 0.9/1000 in non-TOLAC. In the high-risk group, the offspring mortality was 3.7/1000 in TOLAC compared with 0.9/1000 in non-TOLAC, and the 5-minute Apgar score < 4 was 3.1/1000 in TOLAC compared with 0.9/1000 in non-TOLAC. In both risk groups, TOLAC delivery had a higher rate of 5-minute Apgar score < 7. In the low-risk group, non-TOLAC deliveries had a higher rate of neonatal respiratory distress syndrome than TOLAC deliveries.
Conclusions: We observed higher risk of offspring mortality and lower 5-minute Apgar score in TOLAC than in non-TOLAC. Possible causes and preventive measures should be explored.
(© 2018 Nordic Federation of Societies of Obstetrics and Gynecology.)