Pregnancy Labelling Categories
Pregnancy labelling categories were the FDA letter grades once used to summarise fetal risk, replaced since 2015 by narrative pregnancy, lactation and reproductive potential sections.
For three decades American prescription labels graded pregnancy risk with the letters A, B, C, D and X. The Pregnancy and Lactation Labeling Rule replaced that scheme from mid-2015, phasing the letters out and substituting three narrative subsections: pregnancy, lactation, and females and males of reproductive potential. Each contains a risk summary, clinical considerations and the underlying data, so a reader can see whether the evidence is human, animal or absent.
The letters were removed because they compressed incompatible things into one symbol. Category C covered both animal harm and no data at all, and most drugs sat there. Category X differed from D not by degree of risk but by whether any benefit could offset it, which made a grade partly a judgement about indication. A known human teratogen and an entirely unstudied molecule could end up looking similar, while similar molecules landed in different letters.
The narrative format changes what a clinician can conclude. Instead of a grade, the label states the species studied, the exposure multiple at which harm appeared, whether a pregnancy exposure registry exists, and what is known about the disease itself in pregnancy. That last point matters because untreated maternal illness is often the larger risk, a comparison a single letter could never express.
The letters nevertheless persist in apps, reference cards and marketing copy, and are still quoted as though they were current. The specific trap with metabolic peptides is different: labels for long-acting GLP-1 receptor agonists direct discontinuation well before a planned pregnancy because of their week-long persistence, and deliberate weight loss during pregnancy has never been a studied objective.