Time to delivery: Transfers for threatened preterm labour and prelabour rupture of membranes in Western Australia.

Objective: To describe the outcomes of patients transferred to King Edward Memorial Hospital (KEMH) with signs of labour at preterm gestations.

Design: A retrospective observational study of the 69 cases transferred to KEMH during 2015.

Setting: Patient transfers from all locations across Western Australia (WA) to the sole tertiary perinatal centre in Perth.

Participants: Pregnant women within WA with threatened or actual preterm labour (PTL) or preterm prelabour rupture of membranes (PPROM) between 23 and 32 weeks gestation.

Main Outcome Measures: The occurrence of delivery during the admission and time-to-delivery as well as length of admission and association between clinical factors and time-to-delivery.

Results: The percentage of the study population delivered during the admission following transfer was 72.5%. Eighty-six per cent of those who delivered did so within 72 hours of transfer. The median time from transfer to delivery was 1 day. Sixty-three per cent of those who did not deliver during the admission progressed to 36 weeks gestation. Patients transferred with PPROM were less likely to deliver during the admission compared to those with uterine activity (50% versus 19.6%, P = 0.007) and nulliparas were more likely to deliver (93.5% versus 55.3%, P < 0.001).

Conclusion: The majority of women transferred with signs of PTL progress to delivery during the same admission with the highest risk of delivery being the first 72 hours following transfer. If the pregnancy is ongoing at 72 hours, there is a reasonable chance of progression to late preterm gestation supporting the return of woman to their place of origin for antenatal care following discharge.