Is Pregnancy Category C Bad? Debunking the Myth of a Simple Risk Label

October 11, 2025 •

3 min read

In 2015, the FDA replaced the pregnancy letter categories, including the often-misinterpreted Category C, with a more detailed narrative rule. This move came because the old system was often seen as overly simplistic and misinterpreted as a grading scale for risk. So, is pregnancy category C bad? The answer is more nuanced than a simple yes or no, relying heavily on context rather than an arbitrary letter.

Quick Summary

The former FDA pregnancy category C indicated that risk to the fetus could not be ruled out due to limited or inconclusive human data, not that a medication was necessarily unsafe. This system has been replaced by a modern narrative-based approach for a more comprehensive risk assessment.

Key Points

Category C is Obsolete: The FDA discontinued the ABCDX pregnancy category system in 2015 and replaced it with a new, narrative-based rule.
Category C Signified Limited Data: It meant there was insufficient human data and possibly animal study risks, not that a drug was inherently unsafe during pregnancy.
New System Offers More Detail: The Pregnancy and Lactation Labeling Rule (PLLR) provides narrative summaries covering pregnancy, lactation, and reproductive potential, offering more context than a single letter.
Risk Assessment is Individualized: All medication decisions during pregnancy require a careful, personalized evaluation of the potential benefits to the mother versus the potential risks to the fetus.
The Old System Was Misleading: The alphabetical order of the old categories was often misinterpreted as a safety grading scale, leading to unnecessary fear.

The question of 'is pregnancy category C bad?' reflects a common misunderstanding of an old system for classifying drugs during pregnancy. The letter-based categories (A, B, C, D, X), used by the FDA for over three decades, were designed to provide a quick reference for the potential risks of medication during pregnancy. However, they often did more to confuse patients and clinicians than to clarify the actual risks involved. Understanding why the system was changed is crucial to properly assessing medication safety today.

The Shift from Letter Categories to Narratives

For many years, the FDA used a five-tier alphabetical system to classify the potential for a medication to cause fetal harm. While intended to guide decision-making, the system's alphabetical nature led to misinterpretations as a simple grading scale, with Category A perceived as safest and Category X as most dangerous. This was an oversimplification, as the true risk of a drug in Category C was not inherently greater than one in Category B.

Understanding the Old Pregnancy Category C

The former Category C designation was applied when:

Animal studies showed potential fetal harm.
Human data from pregnant women was lacking or inadequate.
Neither animal nor human studies were available in some cases.

Crucially, a Category C label did not prohibit use during pregnancy; rather, it indicated the need for a careful evaluation of potential benefits versus risks. Some examples of medications previously in this category included certain antidepressants and antifungal drugs.

The Problem with the ABCDX System

The FDA recognized that the letter-based system had significant limitations and was often misleading, leading to its discontinuation in 2015. Issues included lack of detail that couldn't convey nuanced risks and misleading interpretation of the system as a simple grade. Inaccurate comparisons could also give a false impression of relative safety.

A New Standard: The Pregnancy and Lactation Labeling Rule (PLLR)

To provide more comprehensive information, the FDA replaced the old categories with the Pregnancy and Lactation Labeling Rule (PLLR) in 2015. This rule mandates detailed, narrative sections on drug labels to facilitate informed decisions by healthcare providers and patients. The PLLR includes three main areas: Pregnancy, Lactation, and Females and Males of Reproductive Potential.

How to Interpret the New Drug Labels

The PLLR provides narrative summaries offering key information. These include a Risk Summary based on human and animal data, Clinical Considerations for guidance, and Background Data detailing study bases.

Comparison: Old vs. New Labeling Systems


Feature	Old Pregnancy Category System (Pre-2015)	New Pregnancy and Lactation Labeling Rule (PLLR)
Classification	Simple A, B, C, D, X letter categories	Narrative summaries for Pregnancy, Lactation, and Reproductive Potential
Data Basis	Primarily relied on animal studies and limited human data	Integrates human and animal data, along with clinical considerations
Interpretation	Often misinterpreted as a linear grading system	Provides context and specific details about risks
Decision-Making	A single letter could oversimplify complex medical choices	Encourages an individualized, informed risk-benefit assessment
Focus	Primarily on fetal risk during pregnancy	Expands scope to include lactation and reproductive potential

Navigating Medication Decisions with Your Healthcare Provider

With the retirement of the old system, discussing medications with your healthcare provider is crucial. Important discussion points include the necessity of the medication, timing during pregnancy, alternative options, potential risks and monitoring, and breastfeeding safety.

Resources like {Link: MotherToBaby https://mothertobaby.org/} can provide additional information and counseling on medication safety during pregnancy.

Conclusion: Beyond a Simple Letter

The question 'Is pregnancy category C bad?' stems from a retired, oversimplified system. The modern approach to medication safety during pregnancy relies on detailed, evidence-based discussions with healthcare providers using the information provided by the PLLR. Moving beyond the old ABCDX categories allows for a more comprehensive and individualized assessment of risks and benefits, which is the safest way to manage medication use during pregnancy.

Frequently Asked Questions

Since the category system was retired in 2015, the former classification is no longer considered the standard. Healthcare providers now rely on the detailed, narrative information provided by the new Pregnancy and Lactation Labeling Rule (PLLR) to assess a medication's risk.

The FDA eliminated the ABCDX system because it was often viewed as overly simplistic and misinterpreted as a grading system. This could lead to a misunderstanding of a drug's true risk during pregnancy.

Not necessarily. Under the old system, Category B was sometimes assigned to drugs with less available data. A Category C drug might have more known effects, both positive and negative, making the blanket assumption that B is 'better' invalid.

Doctors use the narrative information from the new PLLR on drug labels, which includes a risk summary, clinical considerations, and data on human and animal studies. They then weigh the risks and benefits based on the individual patient's health and specific circumstances.

You should discuss it with your healthcare provider. The old category system is not a substitute for a modern, individualized risk assessment. Your doctor will provide the most current information and determine the safest course of action.

You should use caution when consulting online sources. They can be a good starting point for conversation, but you should always confirm information and make decisions with a healthcare professional, who can conduct a full risk-benefit assessment for your specific situation.

The PLLR is the current standard for labeling prescription drugs regarding their use during pregnancy and lactation. It requires narrative descriptions of risks, clinical considerations, and background data, replacing the old ABCDX letter categories.