Cervical Length Surveillance After 24 Weeks in Women With a History of Spontaneous Preterm Birth [09K

Abstract

INTRODUCTION: Cervical length surveillance (CLS) can identify women at increased risk for recurrent spontaneous preterm birth (sPTB) based on transvaginal ultrasound (TVUS). CLS between 24 and 28 weeks is at times performed to administer corticosteroids to women considered at risk of recurrent sPTB. Primary objective was to evaluate the relationship between cervical shortening between 24 and 28 weeks and recurrent sPTB. METHODS: Retrospective cohort study of women with history of singleton sPTB between 24 and 32 weeks, who underwent CLS between 24 and 28 weeks at Lehigh Valley Hospital from 2012-2018. IRB approval was obtained. Exposure of interest was cervical shortening less than 2.5 cm. Primary outcome was delivery less than 37 weeks. Secondary outcomes included rate of antenatal interventions and interval between betamethasone administration and delivery. RESULTS: 3,545 women underwent TVUS for CLS. 118 (3.3%) with CLS between 24 and 28 weeks met inclusion criteria. Cervical shortening was identified in 16 (13.6%) women. Primary outcome was similar among women with short versus normal cervical length. After adjustment, sPTB less than 37 weeks did not correlate with cervical shortening between 24 and 28 weeks, but with clinical preterm labor (AOR 4.02, 95% CI 1.2–13.4; P=.02). CONCLUSION: In our population, the risk of sPTB less than 37 weeks was not predicted by the diagnosis of cervical shortening between 24 and 28 weeks. Our data suggest that the clinical presentation of spontaneous preterm labor, not CLS, is the significant risk factor for sPTB in a subsequent pregnancy for women with a history of sPTB.