Which medications should be avoided during pregnancy?

The phases of pregnancy

Pregnancy corresponds to the period of a child's development in the mother's womb. There are two main phases:

1. The embryonic phase, which covers the first three months of pregnancy, during which the foundation for all the future organs of the baby is established.
2. The foetal phase, which encompasses the following six months, where the baby and its definitive organs develop.

Some medications contraindicated during pregnancy pose even greater risks during the embryonic phase; these are known as teratogenic medications.

Teratogenic medications

Here are some examples of teratogenic medications that are highly toxic to the embryo. Women of childbearing age who must take these treatments should also use contraception:

• Acne treatment: Isotretinoin (Roaccutane®)
• Treatments for bipolar disorder or epilepsy: Sodium Valproate (Epilim®, Depakote®)
• Treatments for multiple sclerosis: Fingolimod (Gilenya®), Teriflunomide (Aubagio®)
• Treatments for multiple myeloma or other blood disorders: Hydroxycarbamide (Hydroxyurea®, Siklos®), Lenalidomide (Revlimid®), Pomalidomide (Imnovid®), Thalidomide (Thalidomide Celgene®)

This list is not exhaustive, other medications are teratogenic. Therefore, it is essential to share your pregnancy plans with your doctor so they can find alternative treatments that do not pose a risk to the foetus.

Medications that are toxic to the foetus

Non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, naproxen, ketoprofen, and diclofenac, as well as aspirin, which are used for inflammation, pain, or fever, are considered foetotoxic medications. They are toxic during pregnancy, particularly from the 6th month onward, when they are absolutely contraindicated.

Indeed, unless otherwise advised by a doctor, even before the 6th month of pregnancy, NSAIDs should not be taken as they can increase the risk of miscarriage or issues with the baby's organ formation or growth. These medications can especially cause potentially irreversible or fatal damage to the kidneys and cardio-pulmonary system.

It is important to remember that during pregnancy, self-medication is not advisable; you should not take medications without a doctor's approval.

Even if you suffer from minor ailments during pregnancy, such as nausea, vomiting, heartburn, or sleep disturbances, it is crucial to implement hygienic and dietary measures first and consult a doctor if necessary. In any case, do not decide to take medication on your own.

In addition to NSAIDs, other commonly prescribed medications are also foetotoxic. For example, in cases of hypertension or heart failure, ACE inhibitors or angiotensin II receptor antagonists, such as captopril, lisinopril, enalapril, valsartan, and losartan, are indicated but contraindicated during pregnancy.

Additional information

For questions and additional information during pregnancy, two websites can be consulted:

• The NHS website
• The UK Teratology Information Service (UKTIS) website

They provide answers to your questions. However, do not hesitate to seek advice from your doctor, midwife, or pharmacist if you have any questions.

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