Cesarean delivery rates at the threshold of viability.

Objective: The purpose of this study was to assess whether the treatment of deliveries at the traditional threshold of viability has become more interventional since the publication of higher survival rates.

Study Design: State vital statistic data from 1995 to 2000 were reviewed to identify deliveries at 22 to 25 weeks of gestation with a birth weight of <1 kg. Demographic data and frequency of cesarean delivery, antepartum bleeding, breech presentation, fetal distress, and cord prolapse were recorded. The cesarean delivery rate and the neonatal mortality rate were calculated for each year. Linear regression for cesarean delivery rate versus year and for neonatal mortality rate versus year were performed at each gestational age.

Results: Of 2924 births that met the study criteria, 1005 births (34.4%) were by cesarean delivery. The cesarean delivery rate at 23 weeks rose from 15.9% in 1995 to 28.2% in 2000 (P =.023). Demographic/obstetric factors did not vary with year of delivery. The neonatal mortality rate remained unchanged.

Conclusion: These data suggest an increasingly aggressive approach to deliveries at the threshold of viability, beginning at 23 weeks of gestation.