Perinatal outcome following prior delivery in the late second or early third trimester.

Forty pregnancies in 37 women who were previously delivered of a live-born fetus between 20 and 32 weeks' gestation are reported here. Fourteen pregnancies were treated with cervical cerclage between 14 and 16 weeks. Twenty-six pregnancies were initially managed conservatively, but three of these patients had a McDonald cerclage placed between 18 and 23 weeks because of significant change in cervical effacement or dilatation. The risk of preterm delivery was 36% (5 of 14) in the cerclage group and 38% (10 of 26) in those patients managed conservatively. The perinatal survival rates were 93% (13 of 14) and 88% (23 of 26), respectively. These results are encouraging when it is considered that only 14% (9 of 64) of prior gestations (exclusive of spontaneous abortions and elective terminations) were carried to term and the perinatal survival rate was 28% (18 of 64). Although this study was nonrandom, these results also support the selective use of cervical cerclage on the basis of past history and physical examination.