FDA Drug Ratings & Teratogens

How and why did the FDA change pregnancy drug classifications?

The old letter system (A, B, C, D, X) was replaced in 2015 with the Pregnancy and Lactation Labeling Rule (PLLR). It was changed because letter grades oversimplified risks, were misleading, and led to false reassurances or unnecessary drug avoidance. The new rule uses narrative risk summaries and clinical data.

Why is it difficult to confirm the safety/risk of drugs during pregnancy?

Pregnant individuals are ethically excluded from clinical trials, limiting data to observational studies and animal models, which do not always reflect human fetal reactions.

What substances should expectant individuals avoid, and what supplement is strongly recommended?

Avoid: Alcohol, tobacco/nicotine, marijuana, illegal drugs, prescription/OTC drugs without medical approval, excessive caffeine, high-mercury fish, and environmental toxins.

Recommended Supplement: Folic Acid (Folate) to prevent neural tube defects (like spina bifida).

When are teratogens most harmful, and why?

During the Embryonic Stage (weeks 2 through 8), because this is the primary critical period of rapid organ formation (organogenesis) when basic bodily structures are being laid down.