Enter your pregnancy or breastfeeding situation to get a simplified interpretation of FDA drug safety information using the Pregnancy and Lactation Labeling Rule (PLLR).
Important: This tool simplifies complex medical information. Always discuss your specific situation with your healthcare provider.
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You’ve probably seen those old letter grades on prescription bottles - A, B, C, D, X. They were supposed to tell you if a drug was safe during pregnancy. But they didn’t. Not really. A Category B drug? That didn’t mean it was safe. It just meant no human studies existed. A Category C? That didn’t mean it was dangerous - just that animal studies showed some risk. Many doctors and patients misread them as simple green/red lights. The FDA knew this was broken. So in 2014, they replaced the whole system with something far more useful: the Pregnancy and Lactation Labeling Rule (PLLR).
The PLLR didn’t just tweak the labels. It rewrote them from scratch. Instead of a single letter, you now get real, detailed information - written in plain language, organized the same way across every drug, and based on actual data. This matters because over 6 million pregnancies happen in the U.S. every year, and most pregnant women take three to five prescription drugs. If you’re pregnant or nursing, knowing what’s in your medication isn’t optional. It’s essential.
The PLLR breaks down drug safety into three clear subsections under Section 8 of the label: Pregnancy, Lactation, and Females and Males of Reproductive Potential. Let’s walk through the first two - the ones that directly affect you if you’re pregnant or breastfeeding.
Section 8.1: Pregnancy has three parts. First, the Risk Summary. This isn’t a guess. It’s a direct assessment: What do we know about harm to the baby? It tells you if the drug caused birth defects, low birth weight, preterm labor, or other problems - based on human data, animal studies, and how the drug works in the body. It also tells you if the risk changes depending on when during pregnancy you took it. Did you take it in the first trimester? That’s different than taking it in week 30. The summary doesn’t hide that.
Next is Clinical Considerations. This is where the real-world advice lives. Does the drug cross the placenta? Does it affect amniotic fluid? Are there dose changes needed during pregnancy? What happens if you stop the drug? For example, some blood pressure meds can cause oligohydramnios - dangerously low amniotic fluid - if taken after 20 weeks. The label now says that clearly. It also tells you if the drug might affect labor or delivery. And if there’s a pregnancy registry? It’s listed here. These registries track outcomes in real women who took the drug - the best kind of data we have.
Finally, Data. This is the evidence behind the summary. It’s not buried in footnotes. It’s laid out plainly: number of women studied, types of outcomes observed, whether results came from case reports, cohort studies, or controlled trials. You don’t have to be a doctor to understand this section - it’s written to help you and your provider make a shared decision.
Section 8.2: Lactation works the same way. The Risk Summary tells you if the drug passes into breast milk, and in what amounts. It doesn’t just say "may be excreted." It says how much - compared to the mother’s blood levels. Is it 0.1%? 5%? That matters. A tiny amount might be harmless. A high amount could affect the baby’s thyroid, brain development, or feeding.
The Clinical Considerations section tells you if the drug affects milk production. Some antidepressants do. It also tells you what signs to watch for in the baby - drowsiness, poor feeding, irritability. And if there’s a known risk, it tells you how to manage it. Maybe you need to time feedings around doses. Maybe you need to pump and discard. Maybe you switch to a safer alternative.
The Data section here gives you the numbers: milk-to-plasma ratios, infant plasma levels, duration of exposure in studies. No more guessing. Just facts.
The old A-B-C-D-X system was easy to remember - but dangerously misleading. A Category B drug? You might assume it’s safe. But what if it’s a drug with no human data at all? That’s still Category B. What if there’s a Category C drug that’s been used safely by thousands of women for 20 years? Still labeled "C." The system didn’t reflect actual risk. It reflected how much we’d studied it.
That created a false sense of security. Doctors avoided Category C drugs, even when they were the best option. Patients refused them, even when not taking them could be more dangerous - like stopping seizure meds or antidepressants during pregnancy. The PLLR fixes this by forcing labels to say: "Here’s what we know. Here’s what we don’t. Here’s the trade-off."
One powerful example: antidepressants. Before PLLR, many were labeled Category C. That scared people away. But the PLLR labels now say: "Untreated depression during pregnancy increases the risk of preterm birth, low birth weight, and postpartum depression. The risk of neonatal adaptation syndrome with this drug is about 30% - and usually mild and resolves in days."
That’s not a letter. That’s context. That’s what you need to decide.
Before PLLR, lactation info was often tucked into the "Nursing Mothers" section - vague, incomplete, and sometimes missing entirely. Now, it’s a full subsection with the same rigor as pregnancy. That’s huge.
Some drugs are perfectly safe in breast milk. Others aren’t. The PLLR tells you which ones. For example, sertraline - a common antidepressant - shows very low levels in milk. The label says so. It even cites studies where infants had undetectable plasma levels. On the flip side, drugs like lithium or certain chemotherapy agents have clear warnings: "Avoid breastfeeding while taking this drug."
The label also tells you about timing. If you’re taking a short-acting drug, you might be advised to breastfeed right after your dose - when levels are lowest. For long-acting drugs, it might recommend spacing feedings. This isn’t theoretical. It’s practical, individualized advice.
You don’t need to be a pharmacist to use the PLLR. Here’s how:
Don’t let fear make the decision for you. Use the label to ask better questions. "What’s the chance this affects my baby?" "What happens if I don’t take it?" "Is there a safer option?" The PLLR gives you the tools to have that conversation.
The PLLR isn’t static. The FDA keeps updating labels as new data comes in. In 2023, they released new guidance to help manufacturers improve clarity - especially around timing of exposure and infant monitoring. More drugs now include detailed case examples, like how stopping a medication improved amniotic fluid levels in a specific week of pregnancy.
There’s also growing alignment with international regulators. The European Medicines Agency (EMA) still uses a different format, but both agencies are working toward more consistent language. That means better global data sharing and fewer confusing differences in labeling.
The biggest change? The requirement for pregnancy exposure registries. Before PLLR, these were optional. Now, they’re mandatory for many drugs. That means more real-world data, faster. And that means safer recommendations for the next generation of moms.
No drug is 100% risk-free during pregnancy or breastfeeding. But the PLLR makes sure you’re not flying blind. It replaces guesswork with evidence. It replaces fear with facts. And it puts the power to decide - with your provider - back in your hands.
If you’re pregnant or nursing and on medication, don’t skip reading the label. Don’t rely on old advice. The PLLR was built for you. Use it.
The PLLR is a U.S. FDA rule that replaced the old pregnancy letter categories (A, B, C, D, X) with detailed, narrative sections on drug safety during pregnancy and breastfeeding. It was finalized in 2014 and requires manufacturers to provide clear, evidence-based information on risks, clinical guidance, and data sources for each drug.
Look in Section 8 of the prescribing information, titled "Use in Specific Populations." It’s broken into three parts: 8.1 (Pregnancy), 8.2 (Lactation), and 8.3 (Females and Males of Reproductive Potential). These are standardized across all FDA-approved prescription drugs and biologics.
No. The PLLR only applies to prescription drugs and biological products regulated under the Physician Labeling Rule. OTC medications follow different labeling rules and may not include the same level of detail on pregnancy or lactation risks.
Animal data is included only when human data is limited. The Risk Summary always prioritizes human evidence - from registries, case reports, and clinical studies. Animal findings are clearly labeled as such and used to support, not replace, real-world observations. The goal is to give you the best available picture, not to overstate uncertainty.
That means no human studies have been done - not that the drug is unsafe. Many drugs, especially newer ones, fall into this category. Your provider should weigh the known risks of untreated illness against the unknown risks of the drug. Sometimes, the benefit of treatment outweighs the unknowns. Don’t assume "no data" means "avoid." Ask for context.
Yes, for many drugs covered under the PLLR. If a registry exists, it will be listed in Section 8.1. These registries collect real-time data from women who take the drug during pregnancy - helping build better safety evidence for future patients. Participation is voluntary but strongly encouraged.