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Safe and Harmful Drugs in Pregnancy

Listed below are some safe drugs and some harmful drugs in pregnancy. Since it is not a complete list, patients are advised to check the drug label of each drug before taking them during pregnancy.

Drugs Considered Safe in Pregnancy

  • Some antibiotics namely Amoxycillin, Ampicillin, Cephalosporins, Erythromycin (not estolate)
  • Levothyroxine
  • Acetaminophen
    (Note: Prenatal exposure of acetaminophen during 18 and 32 weeks of pregnancy may increase the risk of hyperactivity and behavioral problems in children according to a study published in JAMA Pediatrics.)
  • Folic Acid and Vitamin B6
  • Methyl dopa, and hydralazine
  • Insulin
  • Heparin


Drugs Contraindicated in Pregnancy: Some drugs in category X that are contraindicated in pregnancy and their effects on the fetus are listed below:

  • Vitamin A and its derivatives – Accutane(Isotretinoin), Acitretin, Etretinate – Birth defects, miscarriage
  • Thalidomide – Seal like limbs and other defects
  • Diethylstilbestrol – Causes cancer of the vagina or cervix in female children during their teenage years
  • Warfarin – Causes multiple birth defects
  • Danazol – Causes malformations in sex organs of female fetus
  • Simvastatin and other statins – Cholesterol is needed for fetal growth and its reduction by statins could harm the fetus
  • Finasteride – Though finasteride is normally not prescribed to women, pregnant women should not handle broken or crushed tablets since it can get absorbed through the skin and affect the sex organ development of the male fetus.
  • Testosterone – Can cause birth defects
  • Oral contraceptives- Can cause birth defects
  • Dutasteride – Affects the sex organ development of the male fetus.
  • Methotrexate – Causes cleft palate along with multiple defects


Some known side effects of drugs during pregnancy are listed below

  • Tetracyclines – Get deposited in fetal bones and retard their growth, also affect teeth causing them to be discolored and deformed
  • Chloramphenicol – Gray baby syndrome
  • Isoniazid – Neuropthy and seizures in fetus, liver damage in mother
  • Sodium Valproate – Defects of the nervous system
  • ACE inhibitors – Growth retardation, birth defects, fetal death
  • Lithium – Affects fetal thyroid, heart beside causing other abnormalities
  • Phenytoin – Cleft lip/ palate along with other deformities
  • Anti convulsants – Trimethadione, Valproic acid, Carbamazepine – Multiple birth defects
  • Androgens – Multiple defects


During the last 3 months of pregnancy, drugs crossing the placental barrier may interfere with the vital functions of the fetus E.g.:

  • Morphine – If the mother is given morphine during labor, fetal asphyxia can occur
  • Anti-coagulants – May cause fatal bleeding in the newborn
  • Radioactive iodine therapy – A cretin may be born due to radioactive iodine therapy
  • Anti thyroid drugs – may produce goiter, which can lead to face presentation
  • Sulfonamides – may increase bilirubin levels leading to kernicterus

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Categorised in: Obstetrics, Pharmacology

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