http://content.nejm.org/cgi/content/.../111?query=TOC

Results: Of 24,077 repeat cesarean deliveries at term, 13,258 were
performed electively; of these, 35.8% were performed before 39 completed
weeks of gestation (6.3% at 37 weeks and 29.5% at 38 weeks) and 49.1% at
39 weeks of gestation. One neonatal death occurred. As compared with
births at 39 weeks, births at 37 weeks and at 38 weeks were associated
with an increased risk of the primary outcome (adjusted odds ratio for
births at 37 weeks, 2.1; 95% confidence interval [CI], 1.7 to 2.5;
adjusted odds ratio for births at 38 weeks, 1.5; 95% CI, 1.3 to 1.7; P
for trend 0.001). The rates of adverse respiratory outcomes, mechanical
ventilation, newborn sepsis, hypoglycemia, admission to the neonatal
ICU, and hospitalization for 5 days or more were increased by a factor
of 1.8 to 4.2 for births at 37 weeks and 1.3 to 2.1 for births at 38 weeks.

Conclusions: Elective repeat cesarean delivery before 39 weeks of
gestation is common and is associated with respiratory and other adverse
neonatal outcomes.