Does preterm cervical dilatation imply imminent labor in multifetal pregnancies?

OBJECTIVE: Women with multifetal pregnancies are at increased risk of preterm labor and delivery compared with singleton pregnancies. Presentation with advanced cervical dilatation of 3-4 cm is generally regarded as being in the midst of the first stage of labor. The purpose of this report is to present our experience in cases of advanced cervical dilatation and arrested preterm labor in multifetal pregnancies.

METHODS: This study is a retrospective analysis of threatened preterm deliveries in women with multifetal pregnancies. Fifteen cases with advanced cervical dilatation that remained undelivered for at least 10 days are presented and reviewed.

RESULTS: Out of 1219 women presenting with multifetal pregnancies to the high-risk maternity unit, 15 women who presented with advanced cervical dilatation of 3-5 cm and remained undelivered for at least 10 days were identified. Eight women presented with twins and seven with triplets. The mean latency period to delivery was 21.7 days (range 10-43 days). The mean gestational age at diagnosis was 31.3 weeks (range 26.3-35.3 weeks). The mean gestational age at delivery was 34.5 weeks (range 29.5-38.0 weeks). Twelve women delivered vaginally in this group, giving a cesarean section rate of 20%.

CONCLUSIONS: In the women presented in this series advanced cervical dilatation did not lead directly to preterm labor and delivery, we believe due to their having a multifetal gestation. It is possible that dilatation of the cervix in these cases is not a result of preterm labor but rather a relative cervical incompetence resulting from overdistention of the uterus in twins or higher-order gestations. This phenomenon may be underdiagnosed because of a tendency to forego frequent digital examinations remote from term without a clear indication. More information is therefore needed on the mechanism of cervical change during multifetal pregnancy.