To help pregnant women and their healthcare providers choose prescription and OTC drugs safely, the FDA created a grading system, labeling drugs in categories from A (considered safest, with controlled human studies that have shown no fetal risks), through X (drugs that have proven fetal risks that outweigh any possible benefit). Letter categories are chosen based on what studies have shown about the medicine when used in pregnant women and animals. (The FDA is phasing out this system.)
Definition of medicine categories
Pregnancy Category: A
- Folic acid
- Levothyroxine (thyroid hormone medicine)
Pregnancy Category: B
In animal studies, pregnant animals received the medicine, and some babies had problems. But in human studies, pregnant women used the medicine and their babies did not have any problems related to using the medicine.
- Some antibiotics like amoxicillin.
- Zofran (ondansetron) for nausea
- Glucophage (metformin) for diabetes
- Some insulins used to treat diabetes such as regular and NPH insulin.
Pregnancy Category: C
No animal studies have been done, and there are no good studies in pregnant women.
- Diflucan (fluconazole) for yeast infections
- Ventolin (albuterol) for asthma
- Zoloft (sertraline) and Prozac (fluoxetine) for depression
Pregnancy Category: D
- Paxil (paroxetine) for depression
- Lithium for bipolar disorder
- Dilantin (phenytoin) for epileptic seizures
- Some cancer chemotherapy
Pregnancy Category: X
- Accutane (isotretinoin) for cystic acne
- Thalomid (thalidomide) for a type of skin disease
The FDA is changing prescription medicine label information and the pregnancy part of the label will change over the next few years. As this prescription information is updated, it is added to an online information clearinghouse from the NIH and the US National Library of Medicine called DailyMed that gives up-to-date, free information to consumers and health care providers.
Last updated: August 12, 2016