Maternal and perinatal complications by day of gestation after spontaneous labor at 40-42 weeks of gestation

Objective. To evaluate pregnancy outcome after spontaneous labor by day of gestation between 40(+0) and 41(+6) weeks of gestation. Design. Evaluation of prospectively collected labor ward data. Setting. University Hospital, Denmark. Population. Unselected consecutive cohort of 14 678 spontaneously starting deliveries between 280 and 293 days of gestation during the years 2000-2006. Methods. Data were registered in a computer program after each delivery by a midwife and the entries further evaluated by a specialist in obstetrics. Complication rates were compared using Fisher's exact test. Main Outcome Measures. Maternal complication rates for each gestation day, including cesarean delivery, maternal blood transfusion, episiotomy, operative vaginal delivery, third and fourth degree perineal lacerations and perinatal morbidity. Results. The cesarean delivery rate increased from 6% on day 280 to 11% on day 293. Cesarean delivery increased from 40 to 41 weeks gestation (7.3 vs. 9.5%, p<0.005), as did maternal transfusion (0.5 vs. 1.2%, p<0.001) and cesarean section on the indication fetal distress (1.5 versus 2.4%, p<0.005), but perineal lacerations did not. Likewise, there was an increase in episiotomy rates (3.0 vs. 3.5%, p=0.08), operative vaginal delivery (5.8 vs. 6.5%, p=0.07) and admission to neonatal intensive care (1.4 versus 2.0%, p=0.009), but no increase in 5 minute Apgar scores <7 or low umbilical artery acid base values. Conclusions. Deliveries starting spontaneously in an unselected cohort showed an increase in maternal complications, meconium-stained amniotic fluid and admission to the neonatal intensive care unit.