It occurs when amniotic fluid escapes into the mother's circulatory system and causes a blockage which can lead to the mother's death, in certain cases. AFE is one of the leading causes of maternal mortality in developed countries. In Canada alone, it accounted for seven of 44 direct maternal deaths from 1997 to 2000, according to the researchers of the study.
"Of the 180 cases of AFE we found, 24 -- or 13 percent -- were fatal," said lead author Dr. Michael Kramer, a professor of pediatrics, epidemiology and biostatistics at Montreal's McGill University. Dr. Kramer went on to say that "AFE arose almost twice as frequently in women who had medical induction of labor as in those who did not ... fatal cases arose three and one-half times more frequently."
In 17 percent of the Canadian deliveries studied, women were given drugs to induce labor. For every 100,000 women in whom labor was induced, there were up to five cases of AFE -- with up to two cases resulting in the mother's death.
The research team concluded that "Although the small absolute risk of amniotic-fluid embolism is unlikely to affect the decision to induce labor in the presence of compelling clinical indications, women and physicians should be aware of this risk if the decision is elective." The research team's findings on AFE were published in the October 21 issue of the medical journal The Lancet.
As labor-induction rates in the United States approach 20 percent, these new results suggest the practice could be causing the complication in 30 to 40 women a year in the United States, according to the Canadian research team.
In addition to AFE complications, other risk factors for maternal death from complications include maternal age of 35 or older, multiple pregnancies, Caesarean or vaginal forceps delivery, cervical laceration or uterine rupture, eclampsia and fetal distress.