The relative risk of stillbirth following a preeclamptic pregnancy declined dramatically over the last 35 years in Norway, while the relative risk of neonatal death remained stable despite a substantial increase in preterm deliveries, reported Dr. Olga Basso and associates at the National Institute of Environmental Health Sciences and the University of Bergen, Norway.
Data on developed countries show an increasing trend toward managing preeclampsia by inducing deliveries preterm, even before 32 weeks. “Physicians face a real dilemma in balancing the risk of fetal/neonatal/maternal death due to preeclampsia against the increased risk of death associated with preterm delivery,” Dr. Basso and her colleagues wrote (JAMA 2006;296:1357–62).
To assess the effect of changing obstetric management of preeclampsia on fetal and infant survival, the investigators reviewed data from the Medical Birth Registry of Norway collected between 1967 and 2003. The analysis was restricted to singleton pregnancies lasting at least 24 weeks in nulliparous Norwegian-born mothers.
The investigators analyzed 804,448 births, including 33,835 pregnancies complicated by preeclampsia. Births were grouped into three roughly equal periods (1967–1978, 1979–1990, and 1991–2003). Logistic regression analysis was used to estimate preeclampsia-related odds ratios for fetal and infant death.
The incidence of stillbirth among preeclamptic pregnancies decreased sevenfold from the period 1967–1978 to the period 1991–2003.
Over the same time span, deliveries before 37 weeks due to medical intervention in preeclamptic pregnancies increased from 8% to almost 20%.
Notably, the relative risk of infant death following preeclamptic pregnancies remained stable, the investigators reported.
“Modern medical management of preeclampsia appears to have been effective in preventing fetal death without causing an increase in infant or maternal death,” Dr. Basso concluded.