Risk determinants of perinatal mortality in a Swedish county, 1980-1984.

A retrospective case-referent study was performed to analyse risk factors of perinatal mortality. Overweight defined by body mass index, smoking greater than 10 cigs/day, infertility, earlier birth weight, earlier perinatal death were significant risk determinants of the obstetric history. Overweight and smoking, measured by the etiologic fractions, had the greatest impact on perinatal mortality. Significant risk factors of the present pregnancy were low weight gain, pre-eclampsia, cervical incompetence, and late hemorrhage. Intra-uterine growth retardation had the highest etiologic fraction. High risk assessment at the first antenatal visit had a sensitivity of 45%, increasing to 72% when adding supervening pregnancy complications. Although the positive predictive value of high-risk classification was very low, 2/3 of the perinatal deaths occurred among high-risk cases.