The risk factors for unexplained antepartum stillbirths in Scotland, 1994 to 2003

Objective:to determine the factors contributing to unexplained antepartum stillbirth in scotland.study design:a 10-year birth database in scotland was used to compare the unexplained antepartum stillbirth with other birth outcomes. the sample unit was a pregnant mother with a gestational age of 20 weeks and above and with a fetal birth weight of 200 g and above.result:maternal age of 35 years and above, lower deprivation category, inaccessible area of residence, maternal smoking, maternal height of <160 cm and gestational age of above 39 weeks were significantly associated with unexplained antepartum stillbirth. in multivariable analysis only maternal age (adjusted odds ratio (or): 1.8, confidence interval (ci): 1.1 to 3.0, p=0.02), smoking during pregnancy (adjusted or: 2.0, ci: 1.1 to 3.5, p=0.02), and maternal height (adjusted or: 1.4, ci: 1.1 to 1.8, p=0.01), remain significant. screening of pregnancies based on these three risk factors had 4.2% sensitivity and 99.4% specificity. the prevalence of stillbirth for this population was 0.2%. a positive predictive value of only 1.2% implies that only 1 in 83 women with these three risk factors will have antepartum stillbirth. the remaining 82 will suffer needless anxiety and potentially diagnostic procedures.conclusion:advanced maternal age, maternal smoking, and shorter maternal height were associated risk for unexplained antepartum stillbirth but screening based on these factors would be of limited value.