Medicines Contraindicated in Pregnancy


Cecile is feeling ecstatic. Finally, after 2 years of marriage with her husband, they are now having a baby. Oh how long they’ve waited for this day to come. They are both excited as they envision how their baby would look like, what they would name him/her, what things they’d be needing.

However, one thing comes to Cecile’s mind. What will happen if she gets sick, like the flu for example. Will she still be able to take over the counter medications? What are those medicines that she needs to avoid? She thinks deeply as she reminds herself to ask their doctor later on.

What to avoid

Yes, we have known medicines to help in curing some health conditions, but there are also times wherein instead of helping, they may bring unwanted side effects because of not taking into considerations some precautions, take for example in pregnancy. Though it may not show yet, certain drugs may have an effect on the fetus and its development. Below are certain drugs pregnant women must avoid.

  • Vitamin A and its derivatives (Accutane(Isotretinoin), Acitretin, Etretinate)

They may result into birth defects and even 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:

  • 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



Liane Clores, RN MAN

Currently an Intensive Care Unit nurse, pursuing a degree in Master of Arts in Nursing Major in Nursing Service Administration. Has been a contributor of Student Nurses Quarterly, Vox Populi, The Hillside Echo and the Voice of Nightingale publications. Other experience include: Medical-Surgical, Pediatric, Obstetric, Emergency and Recovery Room Nursing.

What Do You Think?