Aspirin. (Drugs, Pregnancy, and Lactation).

Because aspirin is widely used, many women are exposed to it before they know they are pregnant.

Moreover, during the last few years, aspirin has increasingly been used in the preventive treatment of various conditions associated with pregnancy, including hypertension, preeclampsia, and repeated miscarriages, especially those associated with autoantibodies. Overall, aspirin hasn't proven to be very effective in preventing repeated miscarriages. It probably has a small effect on preventing preeclampsia and prematurity.

To further address the concerns about aspirin safety during pregnancy, my colleagues at Motherisk and I conducted a systematic review of all studies of aspirin use in pregnancy that were published in the peer-reviewed literature. We examined whether children exposed to aspirin in utero have more complications than unexposed children. We also did a second study looking at perinatal outcomes.

Our analysis of malformation rates in 22 studies, which will be published in the American Journal of Obstetrics and Gynecology, indicated that aspirin use during the first trimester does not increase the risk of fetal malformations in general. Therefore, if a woman has taken aspirin before she knew she was pregnant or needs to take it during the first trimester, her overall risk of fetal malformations does not increase.

However, four case-control studies included in the metaanalysis comparing infants with gastroschisis to infants without gastroschisis showed about a twofold increased risk for this very rare malformation in children who were exposed to aspirin in utero. When these four studies were considered together, the risk of gastroschisis was about 1 per 15,000 births. Nevertheless, case-control studies do not provide direct proof of such an association.

In addition, a similar association has been found with other cold remedies that were taken by the mother in the first trimester, particularly sympathomimetic amines. We cannot draw any conclusions from the finding that both aspirin and sympathomimetic amines are associated with gastroschisis because they are very different types of drugs.

For the most part, women in our study were taking aspirin for cold symptoms, which raises the possibility that it may be the cold, not the aspirin or sympathomimetic amine, that causes the malformation. It is possible that at least one of the viruses that cause upper respiratory infections may bring about an increased risk of ...