Risk factors of stillbirths in Victoria (Australia): A case-control study

Stillbirth is one of the most adverse pregnancy outcomes. The rate of stillbirth in high income countries has remained stagnant in recent decades. This study aimed to determine the incidence and risk factors of stillbirths specific to hospital-based deliveries in a secondary level hospital in Melbourne, Australia, over a 5-year period. We conducted a case-control study from January 2007 to December 2011. Univariate and multivariate analyses were conducted in STATA 12.1. The 5-year cumulative incidence of still-birth was 5.3 per 1000 total births (95% CI 4.3, 6.5). Univariate analysis revealed that higher body-mass index, smoking during pregnancy, haemoglobin level (≥14.5 g/dl), previous stillbirth, primiparity, marital status, previous caesarean section and reduced foetal movement in the 2 weeks prior to delivery were associated with increased risk of stillbirth. However, after adjustment for confounders in a multiple-regression model, only previous caesarean section (p = 0.006), unmarried (p = 0.004), high haemoglobin level (p = 0.007) and reduced foetal movement in the 2 weeks prior to delivery (p < 0.001) remained significantly associated with increased risk of stillbirth. The characteristics of our study population was similar to the population of state-wide survey in 2009, however, the incidence in our study was slightly lower. We concluded that previous caesarean section, pregnancy while being unmarried, higher haemoglobin level and reduced foetal movement in the 2 weeks before delivery were significant predictors of stillbirth. The identified risk factors were similar to other studies and the obstetric practice at the hospital or the demographics of the study population did not add to additional risk.