Tretogenic drugs in Ist trimester of Pregnancy

⚠️ Major Teratogenic Drugs in the First Trimester

1. Anticonvulsants (Anti-epileptics)

1. Valproic acid / Sodium valproate → Neural tube defects (e.g., spina bifida)

1. Phenytoin → Fetal hydantoin syndrome (cleft palate, growth retardation, cardiac defects)

1. Carbamazepine → Neural tube defects

1. Phenobarbital → Developmental delay

2. Vitamin A Derivatives

1. Isotretinoin / Retinoic acid (used for acne) → Severe birth defects (craniofacial, cardiac, CNS malformations)

1. High-dose Vitamin A → Similar effects

3. Anticoagulants

1. Warfarin → Fetal warfarin syndrome (nasal hypoplasia, bone deformities, CNS defects)

(Note: Heparin is safe)

4. Antibiotics

1. Tetracyclines → Teeth discoloration, inhibition of bone growth

1. Aminoglycosides (e.g., streptomycin, gentamicin) → Ototoxicity (hearing loss)

1. Chloramphenicol → Gray baby syndrome

1. Sulfonamides → Kernicterus (especially near term)

5. Anticancer Drugs (Cytotoxic agents)

1. Methotrexate, Cyclophosphamide, Busulfan → Multiple congenital malformations, growth retardation

6. Hormones

1. Androgens / Danazol → Masculinization of female fetus

1. Diethylstilbestrol (DES) → Vaginal clear cell carcinoma in daughters, uterine abnormalities

7. ACE Inhibitors / ARBs

1. Cause renal damage and oligohydramnios (especially later in pregnancy, but avoid throughout).

8. Antithyroid Drugs

1. Methimazole → Aplasia cutis, choanal atresia

1. Propylthiouracil (PTU) → Safer but still used cautiously

9. Others

1. Thalidomide → Limb deformities (phocomelia)

1. Misoprostol → Limb and cranial nerve defects

1. Alcohol → Fetal alcohol syndrome (growth retardation, facial anomalies, CNS defects)

1. Cocaine → Placental abruption, growth retardation

1. Lithium → Ebstein’s anomaly (heart defect)

🩺 Summary Tip for Exams or Notes

💡 "First trimester = formation → malformations", so avoid any teratogenic drug during early pregnancy.