Over the last three decades, the survival of fetuses following a pregnancy complicated by preeclampsia has improved in Norway, new research shows.
Doctors attribute this change to the increased use of aggressive management of preeclampsia - a complication of pregnancy characterized by high blood pressure that typically occurs after the 20th week of pregnancy.
During the same period, the risk of neonatal death following a preeclamptic pregnancy did not change, according to the report in the Journal of the American Medical Association this week. This is reassuring given the fact that doctors in more recent years were likely treating a greater number of preterm infants.
Induced delivery of very preterm infants is becoming a more common approach for dealing with preeclamptic pregnancies, but its effect on fetal and infant survival has not been determined, Dr. Olga Basso, from the National Institute of Environmental Health Sciences in Research Triangle Park, North Carolina, and colleagues note.
To investigate, they analyzed data for 804,448 infants who were logged in the Medical Birth Registry of Norway between 1967 and 2003.
From 1967 to 1978, the rate of early labor inductions (before 37 weeks) for preeclamptic pregnancies was just 8 percent. From 1991 to 2003, the rate had climbed to nearly 20 percent. Between these two periods, the increased risk of stillbirth with a preeclamptic pregnancy versus a non-preeclamptic pregnancy fell from 4.2-fold to 1.3-fold.
As noted, during the same period, the risk of neonatal death for preeclamptic pregnancies changed very little: the odds ratio in 1967 to 1978 was 1.7 compared with 2.0 in 1991 to 2003. Similarly, no significant changes in maternal death were noted.
“This stability in neonatal risk is remarkable, considering the increasing number of very preterm deliveries in recent years resulting from aggressive obstetric management of preeclampsia,” write Basso and colleagues.
“Modern medical management of preeclampsia appears to have been effective in preventing fetal death without causing an increase in infant or maternal death,” the authors conclude.
SOURCE: Journal of the American Medical Association, September 20, 2006.
Revision date: June 14, 2011
Last revised: by Janet A. Staessen, MD, PhD