Risks associated with cesarean sections in women with placenta previa

To investigate the risks associated with cesarean section performed because of placenta previa.

We retrospectively reviewed the records of 88 women with singleton pregnancies complicated by placenta previa who underwent cesarean sections and those of 176 (control) women with singleton pregnancies who required cesarean section because of complications other than placenta previa.

The duration of gestation was 35.3 +/- 3.6 weeks for subjects with placenta previa and 36.9 +/- 3.8 weeks for the control subjects. The mean birth weight was 2,650 g +/- 75 g for infants of women with placenta previa and 2,644 g +/- 38 g for infants of the control subjects. Blood loss during surgery was greater for women with placenta previa than for the control subjects (1,154 ml +/- 924 ml vs 632 ml +/- 357 ml, p < 0.001). Blood transfusion was required in 13 of 88 (15%) women with placenta previa, compared with 4 of 176 (2.3%) of the control subjects (p < 0.001). An emergency cesarean hysterectomy was performed on 4 of the 88 (4.5%) women with placenta previa, and in none of the control subjects (p < 0.05). The Apgar score was < or = 7 at 5 minutes in 17 infants of the 88 (22%) women with placenta previa, compared with 17 infants of the 176 (11%) control subjects among infants born at > or = 33 weeks' gestation (p < 0.05); among infants with a birth weight > or = 2,000 g, the corresponding numbers were 15 (21%) and 13 (9.2%), respectively (p < 0.05).

Cesarean section in the women with placenta previa was associated with increased blood loss, resulting in a blood transfusion rate 6.5 times higher than in the control subjects. These findings suggest that placenta previa might adversely affect the neonatal outcome.