Is cefdinir category B? Decoding its Pregnancy Risk and the New FDA Rules

October 12, 2025 •

3 min read

For years, cefdinir was classified as a pregnancy Category B medication by the FDA, signifying a lack of demonstrated risk to a fetus in animal studies but no controlled human data. However, in 2015, the FDA deprecated this letter-based system and replaced it with a more detailed narrative format under the Pregnancy and Lactation Labeling Rule (PLLR).

Quick Summary

Historically considered pregnancy Category B, cefdinir now falls under the FDA's newer, narrative-based labeling. A healthcare provider must perform a personalized risk-benefit assessment for use during pregnancy, as human data is limited.

Key Points

Historical Category B Status: Historically, the FDA classified cefdinir as Category B, a designation that was deprecated in 2015.
FDA's New Labeling: The Pregnancy and Lactation Labeling Rule (PLLR) has replaced the letter categories with a more detailed, narrative-based summary of risks and benefits.
Limited Human Data: The classification was based on animal studies showing no harm to the fetus, but there are no adequate and well-controlled studies in pregnant women.
Risk-Benefit Analysis: Cefdinir should only be used during pregnancy if the potential benefits clearly outweigh the potential risks, and this should be determined by a healthcare provider.
Safe for Breastfeeding: Available evidence suggests that cefdinir is likely compatible with breastfeeding, as it has not been detected in human breast milk after a typical dose.
Doctor's Consultation is Essential: Due to the lack of human data and the complexities of the new labeling system, it is crucial for pregnant or breastfeeding individuals to discuss medication use with their doctor.

Understanding the Historical FDA Pregnancy Categories

Before 2015, the U.S. Food and Drug Administration (FDA) used a letter-based system to classify the potential risks of medications during pregnancy. This system ranged from Category A to Category X. Cefdinir's category B assignment meant animal reproduction studies showed no fetal risk, but there were no adequate human studies. This led to some misinterpretation of safety in pregnancy.

The Shift to the Pregnancy and Lactation Labeling Rule (PLLR)

The FDA replaced the letter system with the PLLR in 2015 to offer more comprehensive information. This rule mandates detailed information in three subheadings:

Pregnancy: Summarizes risks from human and animal data and provides clinical considerations.
Lactation: Details potential risks during breastfeeding.
Females and Males of Reproductive Potential: Includes information on contraception, infertility, and pregnancy testing.

The PLLR aims to provide healthcare providers with better data for risk-benefit analysis and shared decision-making with patients.

Cefdinir's Specific Risk Assessment Under the PLLR

The historical Category B status highlights the lack of controlled human studies for cefdinir. The current FDA labeling expands on this:

Animal Studies: Studies in rats and rabbits did not show congenital malformations at high doses. However, some studies indicated maternal toxicity and reduced fetal weight at high doses.
Human Data: There are still no adequate and well-controlled studies in pregnant women.

Under the PLLR, cefdinir should only be used during pregnancy if clearly necessary. A healthcare provider must assess the benefits of treating a bacterial infection against the uncertain risks to the fetus, considering that untreated infections also pose risks.

Comparison of Cefdinir and Other Antibiotics in Pregnancy

Choosing an antibiotic during pregnancy involves considering the infection type and drug safety profile. Many cephalosporins, including cefdinir, are often considered first-choice options, but require caution.


Feature	Cefdinir (Third-Generation Cephalosporin)	Cephalexin (First-Generation Cephalosporin)	Tetracycline (Tetracycline Class)	Fluoroquinolones (Quinolone Class)
Old FDA Category	B	B	D	C (often avoided)
Safety in Pregnancy	Generally considered low risk, but human data is lacking.	Considered one of the safest antibiotic options.	Avoided in pregnancy; can cause permanent tooth discoloration and affect bone growth.	Generally avoided due to potential risks, though human data is limited.
Mechanism of Action	Inhibits bacterial cell wall synthesis.	Inhibits bacterial cell wall synthesis.	Inhibits bacterial protein synthesis.	Inhibits bacterial DNA replication.
Consideration	Used when necessary, particularly for infections where its broader spectrum is beneficial.	Widely recommended and has a longer history of use in pregnancy.	Contraindicated in all stages of pregnancy.	Avoided unless no other options are available.

Cefdinir and Breastfeeding Safety

The PLLR also addresses lactation safety. Cefdinir appears safe for breastfeeding. It has not been detected in human breast milk after a single 600 mg dose. Consulting a healthcare provider is essential.

Conclusion

While cefdinir was previously classified as Category B, the FDA's PLLR has replaced the letter system with detailed narratives. Cefdinir's profile still reflects a lack of human data, requiring a careful risk-benefit assessment by a healthcare professional for use during pregnancy. Pregnant individuals should always consult their doctor for informed decisions about medication. The PLLR provides comprehensive guidance, replacing potentially misleading letter categories. More detailed information is available on the FDA label via DailyMed.

Frequently Asked Questions

No, the FDA deprecated the letter-based pregnancy categories in 2015. Cefdinir's label now uses the Pregnancy and Lactation Labeling Rule (PLLR), which provides a detailed narrative instead of a simple letter grade.

Cefdinir was historically classified as Category B because animal studies showed no evidence of harm to the fetus at typical doses. However, there was a recognized lack of adequate and well-controlled studies in pregnant women.

The PLLR is the current FDA standard that replaces the old letter categories. It provides a narrative summary of risks in three subheadings: 'Pregnancy,' 'Lactation,' and 'Females and Males of Reproductive Potential,' offering a more comprehensive assessment for clinicians and patients.

You should only take cefdinir during pregnancy if your doctor determines it is clearly needed and the potential benefits of treating your infection outweigh the potential risks. An untreated infection can also be harmful to your pregnancy.

Yes, cefdinir appears to be compatible with breastfeeding. Studies have not detected it in human breast milk after single doses. However, you should still consult your healthcare provider to discuss your specific situation.

Cefdinir, along with many other cephalosporins and penicillins like amoxicillin and cephalexin, is considered a lower-risk option for treating infections in pregnancy. Other antibiotic classes, such as tetracyclines and fluoroquinolones, are generally avoided.

The most authoritative and current information is on the FDA-mandated drug label, which you can access via the National Institutes of Health's DailyMed website. This resource provides the narrative summary required by the PLLR.