Cervical change and uterine activity as predictors of preterm delivery

Premature uterine activity and early cervical change have both been shown to be useful in predicting preterm delivery. Prospective studies evaluating weekly uterine activity and cervical change were performed in 20 women, 17 of whom were at risk for preterm delivery, starting at 20 to 25 weeks' gestation. Patients were followed weekly until either 36 weeks' gestation or until the onset of premature labor or delivery. Seven women delivered before 37 weeks' gestation (preterm group). Thirteen women did not require tocolysis and delivered after 37 weeks' gestation (term group). A Bishop score was assessed weekly and the score added to the prior values in order to obtain a cumulative cervical score. A similar process was used to assess uterine activity. The cumulative values of Bishop score and uterine activity were plotted against gestational age in both groups. There was no observed increase in cumulative uterine activity in the preterm group before delivery. However, there was a progressive increase in cumulative cervical change weeks before delivery in the preterm group (p less than 0.05). Despite the small sample size, we conclude that progressive cervical change precedes the onset of labor and may be a better predictor of preterm delivery than is weekly monitoring of uterine activity.