Pregnancy Medication Safety: Why Pregnant People Are Excluded From Trials and How We Can Fix It

Overview

Scientific American investigates why there is so little evidence about medication safety during pregnancy and early childhood, despite widespread prescription use. The discussion centers on the acetaminophen headlines and broader research gaps, explaining how historical practices have protected pregnant people from research rather than through research.

The episode features Tanya Lewis, senior health desk editor at Scientific American, who describes feasible approaches to studying drugs in pregnancy and emphasizes the need for evidence to support informed decisions by pregnant people and clinicians.

Overview and Headlines

The podcast examines recent headlines linking acetaminophen to autism in children and explains that the evidence is weak, with correlations in poorly controlled studies and numerous confounding factors. Tylenol is described as generally safe at prescribed doses, but the discussion underscores ongoing uncertainty around many medications used during pregnancy.

"There is not any good high quality evidence to support this link." - Tanya Lewis

Why Data Are Scarce

The conversation traces historical roots back to thalidomide and explains how Congress responded by mandating controlled studies, while simultaneously classifying pregnant people as a vulnerable group unable to consent. This combination led to a long-standing exclusion from many trials, creating a gap in knowledge about how drugs affect mothers and fetuses alike.

Only a small fraction of clinical trials—fewer than 1 percent—currently include pregnant people, leaving clinicians to navigate decisions with limited, imperfect data. The presenters argue we have been protecting pregnant people from research instead of through it, and stress the importance of studying diseases that matter to maternal and fetal health, such as diabetes, heart disease, infections, and mental health disorders.

"We’ve been protecting pregnant people from research instead of through research." - Tanya Lewis

How to Study Medications Safely

The episode outlines practical research avenues, including observational studies of pregnant people already taking essential medications for chronic conditions, or cases where one pregnancy is exposed to a drug and another is not. It also notes that preclinical work and trials in non-pregnant populations can establish safety signals before drugs are studied in pregnancy and that pregnancy-specific data can be gathered without obscuring consent or safety.

"There are ways to study medications safely in pregnant people." - Tanya Lewis

Lessons from Thalidomide

Using a thalidomide analogy, the podcast suggests that early, small, controlled trials could have identified risks and prevented thousands of birth defects, illustrating why data on pregnancy pharmacology is vital for global health and individual families.

"Thalidomide caused birth defects in tens of thousands of children; a small, well-designed trial could have saved thousands." - Tanya Lewis

Conclusion and Call to Action

Ultimately, the discussion calls for shifting from a protection paradigm to a through-research approach that responsibly includes pregnant people in clinical research, while ensuring safety, consent, and robust study designs. This shift aims to improve outcomes for mothers and babies and to empower evidence-based decision-making in pregnancy care.