The Categories of Drug Safety for Pregnancy
Nevertheless, based on the information they are able to gather through the use of animal drug studies and limited human epidemiological reports, Dr. Uhl says the FDA has dictated a code of federal registry, which delineates five categories of the relative safety of drugs when used during pregnancy. Section 201.57 of the federal drug registry lists the categories as such:
- Pregnancy Category A: Well-controlled studies in pregnant women failed to demonstrate any increased risk to the fetus. Because there have been very few controlled clinical studies in pregnant women, there are very few Pregnancy Category A drugs.
- Pregnancy Category B: No human clinical studies on the drug; but no matter how much of this drug was given to animals during clinical studies, there were no adverse affects on fetuses. Many penicillin antibiotics, such as Amoxycillin, Cephalosporin, and Betapen-VK, as well as Claritin, Naproxin, and most Tylenol acetaminophen products fall into this category.
- Pregnancy Category C: No human studies on the drug; but there have been abnormal findings in animal studies. However, the potential benefits of taking the drug during pregnancy outweigh the possibility of risk to the human fetus. Because the dose of a medication is often pushed to hundreds of times what the planned human dose would be, it's very common to have abnormal animal findings in clinical studies, so the majority of drug products fall into the "C" category. Some examples of "C" medications include Biaxin, Acyclovir, Codiene, Sudafed, Actifed, Chloraseptic throat spray or lozenges, Robitussin, Vicks 44, Albuterol, and Monistat.
- Pregnancy Category D: Abnormal findings have been found in animal studies, and there has been positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience or studies in humans. However, the potential benefits from the use of the drug may be acceptable despite its potential risk. These drugs, such as aspirin, the anticonvulsant Deproic and the antidepressant Depromin, are most commonly used during a life-threatening situation when safer drugs cannot be used.
- Pregnancy Category X: Studies in animals and in humans demonstrate fetal risk such that the potential benefits of taking the drug could not possibly outweigh the risks. Also, drugs that would not normally be taken during pregnancy, such as all contraceptive products, fall within this category, even though the data for those drugs may not indicate a risk during pregnancy. Accutane, Danazol, and Clomiphene Citrate are considered category "X."
Dr. Uhl says it's important to realize that these categories are not always linear in the sense that each level is less safe than the proceeding one. Medications often move from one category to another as new information becomes available, and because the animals studied are stressed beyond normal human consumption levels of any given drug, positive findings in animal studies do not always denote danger to the human fetus when taking a drug.
"A product can move from a 'C' to a 'B' if the animal data looks bad. But then there are less well-controlled studies that produce human data demonstrating no risk," she says. "There have been several drugs, including Acyclovir and Budesonide, that have gone from a 'C' to a 'B' rating, based on epidemiological study or pregnancy registry data."
Pregnancy exposure registries, Dr. Uhl says, are voluntary epidemiological studies based on consumer findings during exposure to a particular drug. Patients that have been exposed to a drug during pregnancy can enroll on their own or through their physician to take part in a study that will follow their pregnancy through its term and report any outcomes, such as whether or not a live birth concluded the pregnancy, and whether or not the baby was healthy.
Since most herbal remedies and homeopathic cures are not regulated by the FDA and have no documented clinical data to suggest their potential risk/benefit status, medical doctors try to steer their patients away from these "natural" cures during pregnancy.
For those of you suffering and sniffling through pregnancy woes, just remember that this, too, shall pass. If you are ill, get plenty of rest, drink lots of fluids and follow your doctor's orders regarding what types of medication will provide the most benefit to you and the least amount of risk to your baby. Remember that birth defects are very rare, even with minimal exposures to possibly teteragenic substances. Taking good care of yourself is the best thing you can do to insure a healthy delivery for your baby, so don't hesitate to take medications if you need them and when they have been prescribed for you.
To take part in a pregnancy registry, women may go to the FDA's Office of Women's Health for information on how to register and for a comprehensive list of ongoing registries.
For women who are concerned about taking a particular drug during pregnancy, Dr. Uhl suggests a visit to The Organization of Teratagen Information Services (OTIS), where there are toll-free numbers listed for free drug information counseling services.