Smoking during pregnancy is associated with an increased risk of placental abruption, a potentially life-threatening condition for both the mother and fetus, according to a report in the American Journal of Epidemiology.

With placental abruption, the placenta detaches from the uterus wall prior to birth, resulting in severe bleeding. Depending on the degree of detachment, up to 40 percent of affected infants die.

Dr. Cande V. Ananth, from the Robert Wood Johnson Medical School, New Brunswick, New Jersey, and Dr. Sven Cnattingius, from the Karolinska Institute in Stockholm, investigated whether the effect of maternal smoking on abruption risk is restricted to the pregnancy during which the mother smokes or whether subsequent pregnancies may be affected as well.

According to the findings, smoking during pregnancy raised the risk of abruption during that pregnancy but seemed to have little impact on the risk in future pregnancies.

Regardless of smoking status, having one abruption greatly increased the risk of another abruption. In women with a prior abruption, the likelihood of having another was increased 5.3-fold for nonsmokers and 10.9-fold for smokers compared with women with no history of abruption.

These findings further reinforce the message that women should reduce smoking during pregnancy, Ananth told Reuters Health.

SOURCE: American Journal of Epidemiology, August 1, 2007.