Ability of a preterm surveillance clinic to triage risk of preterm birth: a prospective cohort study

OBJECTIVE: To identify whether preterm surveillance clinics (PSCs) risk-stratify high-risk women accurately by comparing outcomes of those admitted to hospital on the basis of asymptomatic testing with those not admitted.

METHODS: We performed a subanalysis from a larger prospective cohort study on sonographic cervical length, quantitative fetal fibronectin (qfFN) and risk of spontaneous preterm birth. We identified 1130 asymptomatic singleton pregnancies at high risk of preterm birth, screened between 23 and 28 weeks of gestation at a PSC in a tertiary hospital in London, UK. Gestational age at delivery, the proportion of preterm births that delivered < 30 weeks and neonatal outcomes were compared between women admitted electively when asymptomatic as a consequence of screening-test results and those who were not routinely admitted.

RESULTS: In total, 66 (6%) women attending the PSC were admitted to hospital following asymptomatic screening (inpatient group). The mean gestational age at delivery for those not admitted electively (outpatient group) was at term and was significantly higher than that of those admitted from PSC (38.4 vs 31.2 weeks; P < 0.0001). Preterm birth < 30 weeks' gestation was rare in the outpatient group relative to those admitted (1.32% vs 36.4%; P < 0.0001). Neonatal mortality was 0.188% in the outpatient group compared with 4.55% in those admitted electively (P < 0.0001). The incidence of other complications such as neonatal death, 5-min Apgar score < 7, special care baby unit/neonatal intensive care unit admission, respiratory distress syndrome, intraventricular hemorrhage and low birth weight were significantly lower in those managed as outpatients than in those admitted electively.

CONCLUSION: PSCs measuring cervical length and qfFN accurately triage asymptomatic high-risk pregnant women, enabling those at highest risk of adverse outcome to be identified for elective admission to hospital and appropriate management.