Cervical Length as a Predictor of Latency to Labour in Twin Pregnancies Complicated by Preterm Pre-Labour Rupture of Membranes: A Retrospective Study

OBJECTIVE: Preterm pre-labour rupture of membranes (PPROM), one of the leading causes of preterm delivery, represents a serious economic and psychosocial health care burden. The unpredictability of the interval between PPROM and labour, also known as the latency period, can be unsettling for patients and clinicians alike. In singleton pregnancies, the literature supports the use of ultrasound-determined cervical length to estimate the latency period. METHODS: With this retrospective cohort study, we sought to determine whether a shorter cervical length (≤25 vs. >25 mm) is associated with a shorter latency period in twin pregnancies complicated by PPROM. At McMaster University Medical Centre, a tertiary care centre, we used the Better Outcomes Registry Network (BoRN) database to identify patient records that met our criteria for inclusion over a 5-year period. RESULTS: Forty-three records were included in our analysis. On average, shorter cervical length was statistically significantly associated with a 6-day shorter latency period (P = 0.035). Confounders were controlled for using ANCOVA statistical analysis. A moderate, positive correlation between cervical length and latency period was also identified (r = 0.4). CONCLUSION: Understanding that a shorter cervical length is associated with a shorter latency period can assist clinicians in optimizing maternal counselling and patient care, including triaging transfers to tertiary care centres.