FDA Pregnancy Categories
- Jamie Sorenson
- Dec 19, 2025
- 2 min read
FDA Pregnancy Categories
Update on FDA Pregnancy Risk Information
In 2015, the FDA updated prescription and biological drug labeling by replacing the old pregnancy risk letter categories with more detailed information. The previous five-letter system often confused patients and healthcare providers. The new labeling aims to enhance patient-specific counseling and informed decision-making for pregnant women, though clinical interpretation is still necessary.
The Pregnancy and Lactation Labeling Final Rule (PLLR), effective June 30, 2015, introduced new labeling timelines. Drugs approved after this date use the new format immediately, while those approved from June 30, 2001, will transition gradually. Drugs approved before June 29, 2001, must remove the letter categories by June 29, 2018. Generic drug labels must align with updates to reference drugs, but OTC medicines remain unchanged.
The A, B, C, D, and X categories, used since 1979, were replaced with narrative sections:
Pregnancy (includes Labor and Delivery):
Pregnancy Exposure Registry
Risk Summary
Clinical Considerations
Data
Lactation (includes Nursing Mothers):
Risk Summary
Clinical Considerations
Data
Females and Males of Reproductive Potential:
Pregnancy Testing
Contraception
Infertility
The Pregnancy subsection provides dosing, fetal risk, and registry information. If certain data is unavailable, subsections may be omitted, but the Risk Summary is always required.
The Lactation subsection replaces "Nursing Mothers," detailing drugs that should be avoided during breastfeeding, data on metabolites in milk, and effects on infants.
The Females and Males of Reproductive Potential subsection includes information on pregnancy testing, birth control, and fertility effects.
Why Did the FDA Make This Change?
Many women need medication during pregnancy for chronic conditions. Clear, accessible pregnancy and lactation information helps assess risks and benefits. The old categories were overly simplistic and led to misinformation. The FDA gathered input from various groups and issued the proposed rule in 2008, with public comments invited.
Examples of drugs with the new labeling include Addyi, Descovy, Entresto, Harvoni, and Praluent.
FDA Pregnancy Risk Categories Prior to 2015
Established in 1979, the five-letter risk categories indicated potential birth defect risks. They did not consider risks from breast milk. The categories were:
Category A
No fetal risk in studies. Example: levothyroxine.
Category B
No fetal risk in animal studies, no adequate human studies. Example: metformin.
Category C
Adverse effects in animals, potential benefits may warrant use. Example: gabapentin.
Category D
Positive evidence of human fetal risk, potential benefits may warrant use. Example: losartan.
Category X
Fetal abnormalities demonstrated, risks outweigh benefits. The new system focuses on individual risk assessment rather than broad categories.
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Disclaimer: Posts are for education and entertainment only. No medical advice given. This information is for general knowledge and not meant to diagnose or treat any conditions.
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