P15.07: Cervical length as a predictor of latency to labour in twin pregnancies complicated by preterm prelabour rupture of membranes (PPROM): a retrospective study

Abstract

Objectives: Preterm prelabour rupture of membranes (PPROM) is a significant risk factor for preterm birth, which carries tremendous medical, financial and psychological burden. Predicting onset of labour after PPROM can result in timely interventions, including appropriate transfer to tertiary care centres; this in turn may improve neonatal care and decreased maternal and provider uncertainty. Ultrasound-measured cervical length can predict preterm delivery in singleton pregnancies complicated by PPROM, but no such data exists in twins. Therefore, we sought to determine whether cervical length could predict latency interval in twin pregnancies complicated by PPROM. Methods: Using the BORN Database, we identified 43 twin pregnancies between 2012-2016 complicated by PPROM at McMaster University, Hamilton, Canada. Cervical length was determined by ultrasound measurement. We then compared our primary outcome, latency to labour in those pregnancies with cervical lengths less than 25mm to those greater than 25mm and results were analysed by Mann-Whitney statistical analysis. Additional secondary measures compared the groups on length of stay, PPROM parameters and neonatal outcomes. Results: We determined that the average latency interval in those twin pregnancies with cervical lengths less than 25mm is statistically significantly shorter than in those with cervical lengths greater than 25mm (49.2 vs 196.0 hours, p=0.035). The average length of stay was also significantly greater in those with longer cervical lengths (5.52 vs 11.05 days, p=0.03). Potential confounders such as parity, chorionicity, administration of steroid, erythromycin or magnesium sulfate did not have any significant effect by ANCOVA regression analysis. Conclusions: In those twin pregnancies complicated by PPROM, cervical lengths less than 25mm are associated with shorter latency intervals, which may prompt critical, timely intervention in this group.