Can postpartum measurement of cervical length identify women at high risk of subsequent spontaneous preterm birth? To determine this, researchers from Israel and the United States enrolled 1384 women from 2017 to 2021 in a 5-year prospective cohort single-center study. They measured the mean postpartum cervical length in women who had delivered at term or preterm at 8, 24, and 48 hours and 6 weeks postpartum, with follow-up in their subsequent pregnancies to evaluate gestational age at delivery. This study was conducted in two parts; phase 1 assessed the mean postpartum cervical length as per gestational age at delivery and phase 2 evaluated the gestational age at subsequent delivery in 891 women.

Results showed a markedly shorter mean postpartum cervical length among women who delivered prematurely (before 34 weeks of gestation) compared to those who delivered at term at 8 hours (8.4 vs 22.3 mm), 24 hours (13.2 vs 33.2 mm) and 48 hours (17.9 vs 40.2 mm) in the postpartum period. The cervical length was similar between the groups at 6 weeks postpartum. “The area under the curve was higher for preterm birth screening based on a history of a short postpartum cervix alone than for a history of spontaneous preterm birth alone (0.66 vs 0.57)”. Taken together, a history of spontaneous preterm birth and a short postpartum cervix yielded better results with AUC of 0.74.

Based on these findings, it was concluded that measurement of the postpartum cervical length may identify women at risk of spontaneous preterm birth in a subsequent pregnancy. It may be worthwhile to closely monitor such women in their subsequent pregnancies with earlier interventions to reduce adverse perinatal outcome.

Reference

1. Lauterbach R, et al. Postpartum cervical length as a predictor of subsequent preterm birth-novel insights on an old enigma. Am J Obstet Gynecol. 2023 Apr;228(4):461.e1-461.e8. doi: 10.1016/j.ajog.2022.10.012.