) is a prescription antibiotic. At this time, it is not clear if Bactrim is safe for use during pregnancy. The manufacturer states that pregnant women should not take Bactrim, except in rare situations when the potential benefits outweigh the risks to the fetus.
The U.S. Food and Drug Administration (FDA) uses a pregnancy category system to classify the possible risks to a fetus when a specific medicine is taken during pregnancy. Pregnancy Category C is given to medicines that have not been studied in pregnant humans but do appear to cause harm to the fetus in animal studies. Also, medicines that have not been studied in any pregnant women or animals are automatically given a pregnancy Category C rating.
In animal studies, Bactrim increased the risk of cleft palate. Also, trimethoprim (one of the components of Bactrim) increased the risk of fetal death in rats. Human studies are generally lacking, although some data suggests that the risk for birth defects is probably low. It is thought that Bactrim might contribute to birth defects by decreasing folic acid
; if it is necessary for a pregnant woman to take Bactrim, a folic acid supplement
(at a higher than normal dose for a pregnant woman) might be helpful.
Of possibly greater concern, Bactrim might increase the risk of jaundice and, theoretically, kernicterus (brain damage caused by severe jaundice) in the newborn, especially if a pregnant woman takes Bactrim late in pregnancy.
A pregnancy Category C medicine may be given to a pregnant woman if a healthcare provider believes that the benefits to the woman outweigh any possible risks to the unborn child. If other, more suitable antibiotics are available (and are likely to be effective for treating a particular infection), Bactrim should be avoided. However, if Bactrim appears to be necessary to treat an infection, the benefits may outweigh the potential risks.