5 common medications to avoid during pregnancy

Caleb Ihuarulam

Caleb Ihuarulam

In pregnancy, the well-being of both the mother and the baby is paramount which is why it is vital to know what medications to avoid. While some medicines are safe, others pose potential risks and can affect the mother and baby. Some drugs cause complications during pregnancy. Expecting mothers should carefully review medications before use.

This article will explore five medications to avoid during pregnancy. We will explore the risks and benefits and why you should avoid them.

Non-steroidal anti-inflammatory Drugs (NSAIDs)

Anyone can buy over-the-counter medications from pharmacies, supermarkets, or health food stores. They don’t need a prescription. NSAIDs are one of such drugs. NSAIDs are one of the medications you should avoid during pregnancy. Some of these include: 

  • Acetaminophen or Paracetamol (e.g., Tylenol and Panadol),  
  • Ibuprofen (e.g., Advil), Diclofenac (e.g., Voltaren) 

Non-steroidal anti-inflammatory drugs are used to relieve pain, especially in the first trimester. However, they interfere with fetal development. Taking NSAIDs in the second trimester affects kidney function. The kidney initiates amniotic fluid production at 20 weeks. Insufficient production of amniotic fluid could lead to several complications, such as: 

  • Poor lung development 
  • Skeletal problems, e.g., joint contractures and intracranial haemorrhage 
  • Premature or early delivery  
  • Renal toxicity 
  • Increased risk of miscarriage in the first trimester 
  • Fetal demise in extreme cases  

Taking ibuprofen in the third trimester also closes the fetal ductus arteriosus prematurely. Fetal ductus arteriosus is a major blood vessel. This disrupts blood circulation, leading to fetal pulmonary hypertension and other heart defects. 

It is best to avoid OTC medicines during your pregnancy unless where necessary. Also, you can discuss alternative pain management options with your doctor. 

ACE (Angiotensin-Converting Enzyme) inhibitors 

ACE inhibitors are another medication to avoid during pregnancy. These inhibitors helps to treat cardiovascular conditions like hypertension and heart failure. Drugs like Lisinopril (e.g., Prinivil) and Enalapril (e.g., Vasotec) relax the veins and arteries to lower blood pressure. Regardless of their efficacy, they are risky to use during pregnancy. NSAIDs have been implicated with pregnancy complications in the second and third trimesters. Some of these include: 

  • Increased risk of congenital malformations 
  • The threat of impaired kidney function and eventual renal shutdown  
  • Increased risk of malformations of the fetal cardiovascular system  
  • Low amniotic fluid levels.  
  • Elevated risks of low blood pressure 

If you have prenatal hypertension, consult your doctor for safer management alternatives. 

Retinoids (Vitamin A derivatives) 

Retinoids are another medication to avoid during pregnancy. These vitamin a derivatives are used to treat severe cystic acne and other dermatological conditions. While vitamin A is essential, it is harmful for pregnant women when ingested in high amounts. It is also important to note that retinoids and retinol products are similar but vary in concentration.  

Retinol products contain active forms of vitamin A in lower concentrations, which may be safe during pregnancy. Topical or oral retinoid products (e.g., Accutane and Renova) contain active forms of vitamin A in higher concentrations.  

The topical products pose a high risk for pregnant women. However, oral retinoids are teratogens and even more dangerous for your baby. Isotretinoin and other oral retinoids must never be ingested by women who are: 

  • Trying to conceive or get pregnant 
  • Pregnant  
  • Breastfeeding. 

Medications containing retinoids can cause fetal retinoid syndrome (FRS). FRS is a rare condition characterized by a pattern of mental and physical congenital malformations. The severity and range associated with congenital malformations are variable and depend on the time of exposure in pregnancy. It can lead to infant malformation in up to 20% of cases of reported usage.   

Taking Retinoids like isotretinoin during pregnancy increases the risk of: 

  • Miscarriage. 
  • Premature birth.  
  • Congenital disabilities.  
  • Intellectual and developmental disabilities 

Some mental and physical anomalies caused by isotretinoin include: 

  • Heart abnormalities, e.g., hypoplastic left heart syndrome, ventricular septal defects (VSDs), and tetralogy of Fallot 
  • Central Nervous System (CNS) defects, e.g. cerebral abnormalities, hydrocephalus, microcephaly, spina bifida 
  • Renal abnormalities 
  • Thymus gland abnormality 
  • Parathyroid hormone deficiency.  
  • Growth delays before birth or during infancy 
  • Craniofacial (the skull and facial) abnormalities such as: 
  • Ear abnormalities, e.g. anotia, microtia, micro pinna, small or absent external auditory canals, hearing loss, and stenosis of the ears.   
  • Eye abnormalities, including microphthalmia and hypertelorism)  
  • Facial dysmorphia, including cleft lip, cleft palate, and midface hypoplasia  

Medical professionals advise the use of contraceptives before using these medications. This applies especially to women of childbearing age. Discuss alternative acne treatments with your dermatologist. 


Tetracycline is one of the medications to avoid during pregnancy. It is an antibiotic used to treat bacterial infections and other infectious diseases. However, tetracycline affects the maternal and fetal health during pregnancy. High doses of intravenous tetracycline in the third trimester cause hepatotoxicity. Tetracycline can induce fatty liver disease in pregnant women. This can result in severe hepatic dysfunction, acute liver failure, and eventual death.  

Using tetracyclines in the second and third trimesters discolours the unborn baby’s teeth. This discolouration prevents the enamel from growing and usually has a yellow or brown appearance. Tetracycline can also accumulate in the baby’s bones. This may affect bone growth and hardening, leading to impairment. Researchers recommend that pregnant women above 16 weeks of pregnancy should avoid tetracycline. Your healthcare provider will prescribe the medication when necessary.  

Warfarin (Coumadin) 

Warfarin, a blood thinner, is an oral anticoagulant used to treat and prevent blood clots. It is another medication to avoid during pregnancy. One of the most popular Warfarin brands is Coumadin. It is recommended for people who have  

  • A blood clot in or near the heart that could trigger a stroke or heart attack 
  • Pulmonary embolism (blood clot in the lungs) 
  • Venous thrombosis (blood clot elsewhere in the body) 
  • Arrhythmia 
  • A mechanical artificial heart valve 

Warfarin crosses the placental barrier and can cause bleeding in the fetus. Its use during pregnancy is commonly associated with:  

  • Spontaneous abortion 
  • Stillbirth 
  • Preterm birth 
  • Neonatal death 
  • Fetal Warfarin Syndrome (nasal hypoplasia and a depressed nasal bridge) if taken in the first trimester   
  • Increased risk of fetal malformations if taken in the second and third trimesters   

Warfarin increases the risk of heavy bleeding. Pregnant women should not take it unless they have a mechanical heart valve. 

Speak to your doctor immediately if: 

  • You get pregnant or plan to get pregnant while taking Warfarin 
  • You have a high risk of thromboembolism (obstruction of a blood vessel by a blood clot during blood circulation) 

Discuss the use of effective birth control while taking Warfarin with your doctor.  

Conclusion: General Advice for Pregnant Women 

Remember, every pregnancy is unique. What may be safe for one person may be unsafe for another. Consult with your healthcare provider before starting or stopping any medications during pregnancy. They will provide advice based on your medical history and the risks of each drug. Together, you can make informed decisions that promote you and your baby’s well-being especially by knowing medications to avoid during pregnancy

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Caleb Ihuarulam

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