Is Taking Diet Pills Safe When You Are Pregnant?

If you were taking diet pills before you became pregnant -- or if you feel like you're gaining weight too rapidly during your pregnancy -- you may wonder whether it is safe to take diet pills while you're pregnant. While some diet pills are FDA-approved for use during pregnancy, it's not likely that your obstetrician will want you to use them.

Pregnancy and Weight

During your pregnancy, your body generally needs to gain weight to provide a healthy growing environment for your developing baby. If you were at a healthy weight pre-pregnancy, your obstetrician will likely recommend that you gain 25 to 35 lbs. during your pregnancy, say Drs. Michael Roizen and Mehmet Oz in their book "You: Having A Baby." Even women who were heavy before pregnancy generally need to gain a small amount of weight -- or at the very least, maintain their weight -- during pregnancy.

Supplement Diet Pills

There are two major categories of diet pills: supplements that aren't FDA-approved and ones that are. You shouldn't consider taking a diet pill during pregnancy that hasn't been FDA-approved. This is because supplements aren't required to undergo testing for safety and effectiveness, per the Dietary Supplement Health and Education Act of 1994. That means supplements not approved by the FDA might be unsafe, ineffective or both. Supplements also aren't tested for safety in pregnant women.

FDA-approved Diet Pills

Some diet pills, whether over-the-counter or prescription, have been FDA-approved. While the FDA can't guarantee the safety of a pharmaceutical for use in pregnancy, it nevertheless rates diet pills and other pharmaceuticals on an alphabetical scale. Some diet pills, like Alli and Xenical, have an FDA pregnancy rating of "B," according to Drugs.com. This means that there's no evidence that they might harm a developing baby. Other diet pills, such as Meridia, have pregnancy ratings of "C," meaning that there's evidence of harm to babies in animal studies, but there haven't been human studies.

Guidelines

In general, even if a diet pill has an FDA pregnancy rating of "B," avoid using it during pregnancy without first talking to your obstetrician. This is because risk of harm to the baby from the drug itself isn't the only concern -- there's also the risk that you might not provide your developing baby with sufficient nutrients if you're taking a diet pill. Your obstetrician can help you decide whether the risk of a diet pill during pregnancy is worth the benefit.