For years, doctors and patients relied on simple letter grades-A, B, C, D, X-to decide if a drug was safe during pregnancy. But those letters didn’t tell the full story. They made people think a drug labeled "C" was just "a little risky," when in reality, it could mean anything from "no human data" to "serious animal findings." That’s why the FDA replaced the old system in 2015 with something much more detailed: the Pregnancy and Lactation Labeling Rule (PLLR). Now, instead of a single letter, you get real information-numbers, timelines, risks, and practical advice. If you’re pregnant, breastfeeding, or helping someone who is, learning how to read these new labels can make all the difference.

What Changed with the FDA’s New Drug Labels?

Before June 30, 2015, drug labels used five letter categories:

• A: Human studies show no risk (rare-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-this was the most common)
• D: Clear evidence of human risk, but benefits may outweigh risks (10% of drugs)
• X: Contraindicated in pregnancy-risks clearly outweigh benefits (less than 1%)

These letters were easy to remember, but they were misleading. A "C" didn’t mean "safe if needed." It meant "we don’t know enough." And many people treated "C" like a green light. The FDA found that 68% of healthcare providers misinterpreted the letter system. That’s why they scrapped it.

Now, every prescription drug label has three new sections under Section 8: Use in Specific Populations:

• 8.1 Pregnancy
• 8.2 Lactation
• 8.3 Females and Males of Reproductive Potential

Each section follows the same structure: Risk Summary, Clinical Considerations, and Data. No more guessing. Just facts.

How to Read the Pregnancy Section (8.1)

This is where you find the real meat of the information. Forget the letters. Look for three things:

1. Risk Summary: Numbers, Not Letters

Instead of "C," you’ll see something like:

"The background risk of major birth defects in the U.S. general population is 2-4%. In a prospective cohort of 1,200 pregnancies exposed to [Drug Name] during the first trimester, the rate of major birth defects was 4.8% (95% CI: 3.6-6.3%). This represents a 1.5-fold increased risk compared to background."

That’s powerful. It tells you:

• What the normal risk is (2-4%)
• What the risk is with the drug (4.8%)
• Whether the increase is statistically meaningful (1.5-fold)

This helps you weigh: "Is this extra risk worth the benefit?" For example, if a drug reduces severe seizures during pregnancy, a 2.8% absolute increase in birth defect risk might be acceptable.

2. Clinical Considerations: What to Do

This part gives you actionable steps:

• "Avoid use during the first trimester due to risk of cardiac defects."
• "Monitor fetal growth with ultrasound every 4 weeks after 20 weeks gestation."
• "Consider switching to [Alternative Drug] in the second trimester."

These aren’t vague warnings. They’re clinical instructions based on real data.

3. Data: Where the Info Came From

This section is for the curious or the professionals. It lists:

• Study type (e.g., "prospective cohort," "retrospective case-control")
• Sample size (e.g., "n = 870 pregnant women")
• Limitations (e.g., "no data on exposure beyond 32 weeks," "underrepresentation of Hispanic women")

You don’t need to read this unless you’re digging deep. But if you’re unsure about a recommendation, this is where you check the evidence.

How to Read the Lactation Section (8.2)

Breastfeeding and medications? That’s a whole different question. The old system didn’t even try to answer it. Now, you get specifics:

1. Drug Transfer into Breast Milk

Look for phrases like:

"Maternal serum concentration: 120 ng/mL. Infant serum concentration: 5 ng/mL. Infant exposure: 4% of maternal weight-adjusted dose."

That means the baby gets only 4% of what the mom takes. For most drugs, that’s considered low risk.

2. Potential Effects on the Infant

The label will tell you if there’s any known impact:

• "No adverse effects reported in 90 breastfed infants exposed to [Drug Name]."
• "Case reports of drowsiness and poor feeding in infants exposed to high maternal doses."
• "Monitor infant for irritability, poor feeding, or jaundice."

It’s not just "safe" or "not safe." It’s "here’s what to watch for."

3. Recommendations

Sometimes it’s clear:

• "Breastfeeding is not recommended during treatment."
• "Breastfeeding is compatible with use; no special precautions needed."

Other times, it’s nuanced:

"Consider timing doses to minimize infant exposure-administer immediately after breastfeeding and delay next feeding for 4 hours."

This kind of detail helps you make smart choices without stopping breastfeeding.

What About Fertility and Contraception? (Section 8.3)

This section often gets overlooked, but it’s critical. If a drug can affect fertility or cause birth defects, this part tells you:

• "Pregnancy testing required before starting treatment."
• "Two forms of contraception required during treatment and for 3 months after last dose."
• "Use of hormonal contraception contraindicated due to increased risk of thromboembolism."
• "Reversible infertility reported in 2% of male patients after 6 months of use."

If you’re trying to get pregnant-or avoiding it-this section is non-negotiable.

Why the New System Is Better (Even If It’s Harder)

The old letter system was fast. The new one isn’t. But it’s accurate.

A 2017 FDA study showed that with the old system, 68% of providers misjudged risk. With the new narrative format, that dropped to 31%. That’s a huge improvement.

The downside? It takes time. A 2018 study found 62% of obstetricians felt overwhelmed at first. Pharmacists now spend 5-7 extra minutes per prescription counseling patients. Clinicians report needing 3-5 label reviews before they feel confident.

But here’s the upside:

• You know the actual risk, not a guess.
• You understand when during pregnancy a drug is most dangerous.
• You can compare risks across multiple drugs.
• You can talk to your provider with real data, not vague warnings.

For example, if you’re on an antidepressant and pregnant, you can now ask: "Is the risk of untreated depression higher than the risk of this medication?" That’s a real conversation. The old "C" label didn’t let you have that.

What If the Label Doesn’t Help?

Not every drug has perfect data. Some labels still say: "Limited human data available." That’s frustrating, but it’s honest.

When that happens, turn to trusted resources:

• MotherToBaby: Free, expert advice by phone or chat. They review FDA labels and give personalized guidance.
• TERIS: A clinical database used by OB/GYNs and pharmacists for teratogenic risk assessment.
• FDA’s PLLR Navigator App: Search any drug and pull up the exact labeling section.

These tools take the guesswork out of incomplete labels.

What’s Next for Drug Labeling?

The FDA is working on making these labels even clearer. In 2023, they proposed adding simple visual icons:

• A green checkmark for "safe with monitoring"
• An orange warning triangle for "use with caution"
• A red X for "avoid"

These would appear alongside the narrative text-giving you the quick reference you want, without losing the depth you need.

By 2025, the FDA plans to update 100% of pregnancy-related drug labels. They’re also pushing for better data from underrepresented groups-right now, only 15% of registry participants are Black or Hispanic, even though they make up 30% of U.S. pregnancies.

Bottom Line: What You Need to Do

If you’re pregnant, breastfeeding, or planning to be:

1. Don’t rely on old advice or internet rumors. Always check the current FDA label.
2. Look for the three sections: Pregnancy, Lactation, Reproductive Potential.
3. Focus on the Risk Summary and Clinical Considerations first-they’re your action plan.
4. If the label is unclear, call MotherToBaby (1-866-626-6847) or ask your pharmacist to pull up the official labeling.
5. Remember: A "C" doesn’t mean "don’t take it." A 4% infant exposure doesn’t mean "dangerous." Context matters.

The goal isn’t to avoid all risk. It’s to make informed choices. The new labeling system gives you the tools to do just that.