Drug-induced labor may lead to rare but insidious complication

A study published in the Lancet Medical Journal has reported that women who are given drugs to induce labor are nearly twice as likely to suffer from amniotic fluid embolism, a rare but potentially fatal syndrome.

An amniotic-fluid embolism is said to arise when a simultaneous tear occurs in the fetal sac and in the vessels surrounding the uterus, allowing amniotic fluid to seep into the mother's circulatory system.

The study was conducted by the researchers for the Maternal Health Study Group of the Canadian Perinatal Surveillance System. They studied more than three million deliveries of babies in Canada over a 12-year period.

In 185 cases, women experienced the rare complication in which the amniotic fluid that surrounds a baby in the womb enters the bloodstream and causes a blockage. In 24 of these cases, the mothers died.that the study marks the first time that anything has been identified as a

The authors of the study state that the risk of increase of amniotic fluid embolism for women undergoing medical induction of labor is very small. They claim that in every 100,000 women induced, there were up to five embolism cases with up to two of those resulting in death.

The study suggested 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 researchers also recorded a higher rate of amniotic-fluid embolisms among women with diabetes, pre-eclampsia, older women and with caesarean, vacuum and forceps assisted deliveries.

Dr. Michael Kramer, lead author of the study and scientific director of the Institute of Human Development and Child and Youth Health at the Canadian Institutes of Health in Ottawa, Ontario, claims that, "The suspicion that induction of labor might be involved has been there for a couple of decades, but it has been unsubstantiated."

James Walker, Professor of obstetrics at Pittsburgh University claimed that there would be factors other than drug induction that brought on embolism, which the study did not identify. The relationship between induced labor and amniotic-fluid embolism is, so far, just an association, not one of cause-and-effect.