Drugs in Pregnancy & Lactation

Introduction & guiding principles

• Pregnancy is the "last true therapeutic orphan" — ethical, medicolegal and fetal-safety concerns mean almost no drug trials are done in pregnant women, so most labels carry "no adequate well-controlled studies… use only if clearly needed."
• The clinician's core task is a risk–benefit balance: fetal drug risk (chiefly teratogenesis) is weighed against the risk to mother and fetus of the untreated maternal disease — the latter is often wrongly omitted, leaving pregnant women under-treated.
• Indian PG framing — drugs should generally be avoided; if required, used cautiously balancing risk vs benefit for both — for many diseases one or two agents are known to be reasonably safe (e.g. methyldopa for hypertension, chloroquine for malaria).
• Baseline (background) risk — even with no teratogenic exposure, the population risk of a major congenital malformation is ~3% (3–5%); minor anomalies add 7–14%. Drugs cause <1% of all birth defects (~65–80% unknown cause, ~15% chromosomal); fewer than 30 drugs are proven human teratogens.
• Counselling matters — ~50% of pregnancies are unplanned and patients often assume every drug is a teratogen; evidence-based counselling demonstrably prevents unnecessary terminations.