According to an article in the journal American Family Physician, around 80 percent of American women take some type of over-the-counter or prescription drug during their pregnancy. Although some of these drugs are safe in small doses and some (such as nicotine replacement therapy to quit smoking) may have benefits that outweigh the risks, there are still considerable dangers. Increased risk of fetal abnormalities and miscarriage has been linked to even common over-the-counter medicines like aspirin.
The Food and Drug Administration classifies over-the-counter and prescription drugs according to their potential risk to the fetus of a pregnant woman in the first, second, and third trimester of pregnancy. Category A drugs have shown no risk to the first trimester fetus of pregnant women, while Category B drugs have shown no risk in animal studies or have shown risk in animal studies but have shown no risk in human studies. There have either been no studies conducted on drugs classified as Category C or D, or the studies show a risk but the benefits of the drug may outweigh the potential for harm. FDA-classified Category X drugs are harmful to the fetus and the benefits are not believed to ever outweigh the risks of miscarriage or birth defects; therefore these drugs should never be taken by pregnant women or those who plan to become pregnant.
Most drugs classified under Category X that are associated with an increased risk of miscarriage are prescription only. These include the acne treatment isotretinoin, cholesterol-lowering drugs such as Lipitor, radioactive iodine, hormonal contraceptives including the morning-after pill, and the cancer treatment DES. Misoprostol and mifepristone are known to cause miscarriage and may be prescribed to either cause an abortion or to help an already occurring miscarriage along. Category D over-the-counter medicines may increase risks of birth defects or miscarriage and include aspirin and nicotine replacement therapies.
According to Vitaminsdiary.com, many herbal supplements that can be purchased at a health food store may cause miscarriage. Herbs including blue and black cohosh, basil root, and goldenseal may trigger uterine contractions, leading to miscarriage if you are not full term in the pregnancy. Other herbs such as ginseng and mugwort may cause birth defects. Tell your doctor about any herbal supplement you are taking, even if it is believed to be safe.
Most over-the-counter medicines should be taken only in the minimum dose necessary to control symptoms, and with the least toxic drug of the category (acetaminophen over aspirin for headaches, chlorpheniramine over guaifenesin for bad colds) used. The risks of birth defects and miscarriage from many over-the-counter drugs is very mild, and sometimes the benefits outweigh the risk of harm to the fetus.
All over-the-counter drugs taken should be taken at the minimum effective dose to lower the risk of miscarriage or birth defects. Talk to your doctor about any medicines or herbal supplements you take or plan on taking.