A CASE-CONTROL STUDY OF INTRAPARTUM STILLBIRTHS

Objective To determine antenatal and intrapartum risk factors for intrapartum stillbirths in a total population. Design Matched case-control study. Setting Western Australia 1980-1983. Subjects Intrapartum stillbirths of greater-than-or-equal-to 1000 g birthweight (cases) and liveborn infants (controls) individually matched for year of birth, plurality, sex and birthweight of infant and race of mother. Results Intrapartum stillbirths were more likely than controls to have had placental abruption (OR = 9.55, CI = 2.09-43.69), fetal distress (OR = 4.64, CI = 1.92-11.19), cord prolapse (OR = 10.00, CI = 1.17-85.60) and unhealthy placentas (OR = 2.26, CI = 1.13-4.52), and more likely to have been born by vaginal breech manoeuvre (OR = 3.51, CI = 1.40-8.80) and emergency caesarean section (OR = 2.15, CI = 1.13-4.10); mothers of intrapartum stillbirths were less likely to have had no labour (OR = 0.14, CI = 0.04-0.55) and to have been delivered normally (OR = 0.20, CI = 0.10-0.40). Mothers of cases born by emergency caesarean section had longer labours than mothers of controls born by this method. All intrapartum stillbirths with breech presentation were born by vaginal breech manoeuvre compared with only 53% of the controls; the remainder of the controls were born by caesarean section. Conclusions Results indicate that little could have been done early in pregnancy to prevent the intrapartum stillbirths as no antenatal risk factors predicted these deaths. Most of the risk factors identified related to labour and delivery problems. Considering cases born by emergency caesarean section, delivery of the mother earlier in labour may have prevented some of the deaths.