It can be hard to assess whether a particular drug is safe for use during pregnancy. Often, drugs haven’t been tested enough in human pregnancies, and sometimes test results are inconclusive. Labetalol, a drug used to treat high blood pressure, is one medication that has been primarily tested on pregnant animals rather than human beings. Animal testing revealed that the medication is potentially dangerous for human fetuses. Though it has not been studied enough to provide a conclusion for human pregnancies, many doctors are hesitant to prescribe it for pregnant women.
Animal studies of labetalol in pregnancy have revealed a potential for adverse effects. Some studies have shown that animal fetus deformities are unlikely as a result of taking this medication, but other studies demonstrated that rat fetuses and newborns had less chance of survival when exposed to this drug. Likewise, some animal studies have shown an increased risk that the body will reabsorb the fetus, resulting in pregnancy loss. The dosage amounts used in animal testing are usually far above those taken by a pregnant human female, however.
While there is a lack of reliable research evidence regarding the use of this drug in human pregnancies, some retrospective studies have proven revealing. Such studies are performed after a woman has already used the drug in pregnancy, and often, after she has given birth. Some retrospective studies of labetalol in pregnancy have revealed that its use may increase the risk of birth defects in human infants. Likewise, some studies have shown that labetalol may contribute to growth retardation of the fetus. Rarely, this drug might cause low blood sugar and low blood pressure in a newborn of a woman who has taken it for a long period of time.
Despite the discouraging evidence against the use of this drug in pregnancy, it’s harmfulness is not considered definite. Many women have taken labetalol in pregnancy without any ill effects for them or their unborn children. Still, most medical experts recommend cautious use of this medication and only prescribe it when the need for treatment is worth the risk. For example, a doctor may prescribe labetalol in pregnancy when a woman’s high blood pressure is not well-controlled or if she responds best to this medication. A doctor may also prescribe it if other available medications are considered more risky or when other drugs cause a woman to suffer intolerable side effects.