How to Read Pregnancy and Lactation Labeling on Drugs: A Clear Guide for 2026

For years, doctors and patients relied on simple letter grades - A, B, C, D, X - to guess if a drug was safe during pregnancy. But those letters didn’t tell the whole story. They made people think a drug was either "safe" or "dangerous," when the truth is far more complicated. In 2015, the FDA replaced that outdated system with something much more useful: the Pregnancy and Lactation Labeling Rule (PLLR). Now, instead of a single letter, you get real details - numbers, timelines, risks, and data - to help make smarter choices. If you’re pregnant, breastfeeding, or helping someone who is, learning how to read these new labels isn’t just helpful - it’s essential.

What Changed with the FDA’s New Drug Labels?

Before June 30, 2015, drug labels used five letter categories to summarize pregnancy risk:

• A: Human studies show no risk (less than 2% of drugs)
• B: Animal studies show no risk, but human data is limited (about 15% of drugs)
• C: Risk can’t be ruled out (70% of drugs - the catch-all)
• D: Evidence of human risk, but benefits may outweigh risks (about 10% of drugs)
• X: Contraindicated in pregnancy - clear danger (less than 1% of drugs)

These categories were misleading. A "C" didn’t mean "maybe risky" - it meant "we don’t have good data," but many doctors and patients treated it like a red flag. The FDA found that 68% of people misinterpreted these letters. That’s why they scrapped them.

Now, every prescription drug label has three new subsections under Section 8: Pregnancy (8.1), Lactation (8.2), and Females and Males of Reproductive Potential (8.3). Each one follows the same format: Risk Summary, Clinical Considerations, and Data. No more guessing. Just facts.

How to Read the Pregnancy Section (8.1)

The Pregnancy section is the most detailed. It doesn’t say "safe" or "not safe." It tells you what you need to know to weigh the real risks.

Risk Summary gives you the baseline. It starts by reminding you that every pregnancy carries a 3% chance of major birth defects and a 10-20% chance of miscarriage - even without any medication. Then it says: "This drug is associated with a 1.5-fold increased risk of neural tube defects." That doesn’t mean 1.5 out of every 10 babies will have a defect. It means the risk goes from 3% to 4.5%. That’s a real difference, but not a disaster.

It also tells you when the risk happens. For example: "Exposure during the first trimester is linked to cardiac defects." That’s critical. If you’re taking a drug and you’re 12 weeks pregnant, you’re past the highest risk window. If you’re 6 weeks, you need to act.

Clinical Considerations gives you action steps. This is where you find:

• When to test for pregnancy before starting the drug
• What kind of birth control to use (and how effective it is)
• How often to monitor fetal growth
• Whether to adjust the dose during pregnancy

For example, a label might say: "Use a reliable contraceptive with a failure rate under 1% during treatment. Test for pregnancy before each dose if you’re sexually active. Monitor fetal growth every 4 weeks after 20 weeks gestation." No vagueness. Clear instructions.

Data is the fine print - but it matters. It tells you how the evidence was gathered: "Prospective cohort of 1,200 pregnant women, followed from first trimester." Or: "Retrospective analysis of 300 cases, limited by recall bias." This helps you judge how much trust to put in the numbers.

Understanding Lactation Labeling (8.2)

Breastfeeding and meds? The old system ignored this completely. Now, it’s required.

The Lactation section answers three key questions:

1. How much of the drug gets into breast milk?
2. Is the baby exposed to enough to cause harm?
3. Are there documented side effects in infants?

Look for numbers like: "Infant exposure is estimated at 5% of the maternal weight-adjusted dose." That’s low. Or: "Peak milk concentration is 2.3 mg/L at 2 hours after maternal dose." That’s specific. It’s not "maybe safe." It’s "here’s the actual amount your baby gets."

It also says: "No adverse effects reported in 50 breastfed infants." Or: "One case of drowsiness reported in an infant with prolonged exposure." That’s not a warning - it’s a fact. You can decide if that’s acceptable for your situation.

Some labels even include pharmacokinetic data: "Half-life in milk is 4.5 hours. Dosing 12 hours apart reduces infant exposure by 80%." That’s gold for moms trying to time feedings.

What About Fertility and Contraception? (8.3)

This section isn’t just for women. It’s for anyone who can get pregnant - or whose partner can.

It tells you:

• Do you need a pregnancy test before starting the drug?
• What kind of birth control is required? (And what failure rate that method has)
• Is there a risk of infertility? And if so, is it reversible?

For example, a drug for psoriasis might say: "Women of reproductive potential must use two forms of contraception with a combined failure rate under 1%. Pregnancy test required within 7 days before starting. Discontinue drug 3 months before attempting pregnancy due to long half-life."

Men aren’t left out either. Some labels now say: "Drug may reduce sperm count. Sperm banking recommended if planning future fertility."

Why This Matters More Than You Think

You might think, "I’ll just ask my doctor." But doctors are busy. And many still rely on outdated memory or apps like MotherToBaby because the labels are too long to read quickly.

A 2021 survey found that 64% of pharmacists say patients ask more questions about pregnancy risks now - and 78% spend 5-7 extra minutes counseling per prescription. That’s because the new labels are clearer, but they require time to understand.

The real win? Better data. Since the PLLR started, pregnancy exposure registries - where women voluntarily report what meds they took and what happened to their babies - have grown from 5,000 pregnancies per year to over 25,000. That’s how we learn what’s truly safe. And it’s working.

How to Use These Labels in Real Life

Here’s how to make sense of them when you’re in a hurry:

1. Start with Risk Summary. Look for the background risk (3% birth defects) and the drug’s added risk. Is it a small increase? Or a big one?
2. Check the timing. Does the risk apply to the first trimester? Or later? If you’re past that window, your risk drops.
3. Read Clinical Considerations. What do you need to do? Test? Contracept? Monitor? This tells you what’s actionable.
4. Look at Lactation. Is the infant exposure under 10%? Are there any reported side effects? If yes, how many?
5. Don’t skip Data. If the study had only 20 women, take it with a grain of salt. If it’s a 1,000-person study, trust it more.

Pro tip: Use the FDA’s free PLLR Navigator app. It lets you search by drug name and pulls up the key points in plain language. No jargon. Just what you need.

What If the Label Is Still the Old Letter System?

Some older drugs - especially generics - still have the old A, B, C, D, X labels. That’s not because they’re unsafe. It’s because manufacturers were given until 2020 to update them. The FDA says all new drugs must use the new format. But many older ones haven’t been touched.

If you see an old label, don’t assume it’s outdated. Instead, look up the drug on the FDA’s website or use MotherToBaby or TERIS (Teratogen Information System). These are free, trusted databases that translate old labels into the new narrative format.

Common Mistakes People Make

• Mixing up relative and absolute risk. A "2-fold increase" sounds scary. But if the background risk is 1%, a 2-fold increase means 2%. That’s still low.
• Ignoring the timing. A drug might be risky only in the first 8 weeks. If you’re 20 weeks along, that risk doesn’t apply.
• Thinking "no data" means "dangerous." "No human studies" doesn’t mean "harmful." It just means we don’t know yet.
• Assuming breastfeeding = safe. Some drugs are safe in pregnancy but not in milk. Others are the opposite.

What’s Next for Drug Labeling?

The FDA is working on visual aids - simple icons that show risk levels at a glance. Think traffic lights: green for low risk, yellow for caution, red for high risk. That’s coming soon.

By 2025, the FDA plans to update every pregnancy-related label. They’re also pushing for more diverse data - right now, only 15% of registry participants are Black or Hispanic, even though they make up 30% of U.S. pregnancies. Better data means better safety for everyone.

When to Call Your Doctor

You don’t need to become an expert. But you should call your doctor if:

• You’re trying to get pregnant and take a prescription
• You’re pregnant and started a new drug
• You’re breastfeeding and need to start or stop a medication
• The label says "use contraception" but you’re not sure which method works best

Don’t stop a drug on your own. Sometimes, the risk of stopping is worse than the risk of staying on it. For example, untreated depression during pregnancy can lead to preterm birth or low birth weight. A medication that’s "C" or "D" might be safer than going without.

Next Steps for Patients and Providers

If you’re a patient:

• Ask your pharmacist or doctor: "Can you show me the current pregnancy and lactation label for this drug?"
• Bookmark MotherToBaby.org or call 1-866-626-6847 for free, expert advice.
• Use the FDA’s PLLR Navigator app to search drug labels on your phone.

If you’re a provider:

• Update your clinical decision tools to include PLLR data.
• Use the FDA’s free training modules to refresh your knowledge.
• When in doubt, refer to pregnancy registries - they’re your best source for real-world outcomes.

The goal isn’t to scare you. It’s to give you the facts - so you can make the right choice for you and your baby.