Predicting mode of delivery using mid-pregnancy ultrasonographic measurement of cervical length.

BACKGROUND It has been recognized that preterm labor is related to short cervical length and that poor progress in labor is a major indication for cesarean section at term. We therefore hypothesize that long cervix is not associated with increased risk of cesarean delivery during labor at term. OBJECTIVES The objective is to determine the relationship between cervical length at mid-pregnancy and mode of delivery and preterm delivery. MATERIALS AND METHODS Trans-vaginal ultrasonographic scan measurement of cervical length was done for 281 pregnant women at a mean gestational age of 22 weeks. These women were followed up till delivery and the mode of delivery and the cervical length were analyzed for associations. RESULTS Cesarean section due to poor progress in labor at term constituted 11.7%. The cesarean section for the highest quartile cervical length (40-67 mm) was 50% (P value 0.0018 for trend). Of the 33 women whose mode of delivery was cesarean section due to poor progress 18 (54.5%) had cervical length of more than 40 cm. The likelihood ratio of cesarean section due to poor progress of labor at term among women at the upper quartile cervical length is 10.28 (P value 0.0013) CONCLUSION Long cervical length at mid-pregnancy predicts the possibility of cesarean delivery early in pregnancy. Hence, cervical length in mid-pregnancy can be of value in predicting the mode of delivery in early pregnancy.