Born before arrival in NSW, Australia (2000-2011): a linked population data study of incidence, location, associated factors and maternal and neonatal outcomes

Abstract

Objectives: To determine incidence, associated factors, outcomes and geographical occurrence of born before arrival (BBA) in New South Wales, Australia.

Design: A linked population data study involving population-based surveillance systems was undertaken for the years 2000-2011.

Setting: New South Wales, Australia.

Participants: All women who underwent BBA compared with women who birthed in hospital/birth centre settings.

Results: During the time period, there were 1 097 653 births and a BBA rate of 4.6 per 1000 births. The BBA rate changed from 4.2 to 4.8 per 1000 births over time (p=0.06). Neonates BBA were more likely to be premature (12.5% compared with 7.3%), of lower birth weight (209.8 g mean difference) and/or be admitted to a special care nursery or neonatal intensive care unit (20.6% compared with 15.6%). The perinatal mortality rate was significantly higher in the BBA cohort (34.6 compared with 9.3 per 1000 births). Women in the BBA cohort were more likely to be in the lowest socioeconomic decile, multiparous, have higher rates of smoking (30.5% compared with 13.8%) and more likely to suffer a postpartum haemorrhage requiring transfusion than the non-BBA cohort (1.5% compared with 0.7%). The most commonly occurring complications for neonates were suspected infection (6.9%), hypothermia (6.9%), respiratory distress (5.4%), congenital abnormality (4.0%) and neonatal withdrawal symptoms (2.4%). BBA more commonly occurred in geographical areas where the distance to a maternity unit is >2 hours drive and in coastal regions where there is also a high rate of homebirth.

Conclusion: BBA occurs more frequently in multiparous women of lower socioeconomic status. There potentially is an effect of geography on the occurrence of BBA, as geographical area of high homebirth and BBA coexists, indicating that freebirth followed by an unplanned transfer to hospital may be occurring.

Keywords: birth; data linkage; homebirth; neonatal mortality.

Figure 1

Percentage of BBA events according to maternal parity. BBA, born before arrival.

Figure 2

Index of relative socioeconomic advantage and disadvantage comparing BBA events, non-BBA births and homebirth with trend lines. BBA, born before arrival; SEIFA, Socio-Economic Indexes for Areas.

Figure 3

Visual representation of BBA events and homebirth events in NSW. BBA, born before arrival; NSW, New South Wales.