Cervical dilatation and prematurity revisited.

Cervical examination between 26 and 30 weeks' gestation is described as a method for identifying women at risk for delivery before 34 weeks. Blinded cervical examinations were performed in 185 consecutive women, and 15 (8%) were found to have cervixes dilated 2 or 3 cm. The incidence of delivery before 34 weeks' gestation was 27% in such women compared with 2% in those whose cervixes were undilated or 1 cm. Other factors linked to cervical dilatation included parity and prior preterm delivery. However, parous women with cervical dilatation remained at increased risk for delivery before 34 weeks' gestation. We conclude that early third-trimester cervical examination may be an important adjunct in identifying women at risk for preterm delivery.