Closing the pregnancy data gap: new guidelines push to include pregnant people in clinical trials

Pregnant and breastfeeding individuals are among the most medically underserved populations in clinical research. Despite routinely needing medications for conditions like hypertension, epilepsy, depression, and autoimmune disease, they are almost universally excluded from the trials that establish whether those treatments actually work — and are safe.

New draft guidelines from the International Council for Harmonization (ICH E21) aim to change that. Rather than automatic exclusion, the framework calls for a structured, case-by-case assessment of when including pregnant or breastfeeding participants is appropriate, what safeguards are needed, and how to collect meaningful safety data — including for infants. Drug developers would be required to consider this early in a medicine's development, not as an afterthought post-approval.

Experts at a recent EMA meeting in Amsterdam broadly supported the move, emphasizing that exclusion from trials creates an "illusion of caution" — leaving patients, babies, and clinicians making high-stakes decisions with little to no data.

By the Numbers:

• ~90% of pregnant people take at least one medicine during pregnancy
• 71% of available medicines have no pregnancy-use information
• Only 5% have adequate safety data for use during pregnancy and breastfeeding
• It can take 20+ years to establish precise pregnancy risk through post-market studies
• ~2,500 public comments were submitted on the draft E21 guideline

Why it matters: Without trial data, pregnant patients are often forced to choose between undertreated illness and untested medications. These guidelines could fundamentally reshape how evidence is generated for one of medicine's most overlooked populations.