Medicines in pregnancy: risks to the baby and precautions

Can I take medicines while pregnant?

Yes, and sometimes it is essential: a poorly treated illness in the mother (infection, high blood pressure, epilepsy, depression, diabetes) can be more dangerous for the baby than the treatment itself. The aim is to treat the mother while exposing the baby as little as possible.

Most medicines cross the placenta. For some, there is reassuring data from thousands of pregnancies; for others, the data is insufficient and caution is needed; a few are clearly dangerous. Each prescription is therefore decided case by case, depending on the stage of pregnancy, the illness, the length of treatment and the alternatives.

Your pregnancy care through to the birth is described on the Childbirth in Paris page. Tell every health professional you see that you are pregnant, or planning a pregnancy, including your dentist and pharmacist.

How does the risk of a medicine change with the stage of pregnancy?

Some medicines can also have long-term effects on the child's development, such as valproate (see below). This is why monitoring does not stop at the absence of a visible birth defect.

Which medicines should I avoid during pregnancy?

Non-steroidal anti-inflammatory drugs (NSAIDs)

Ibuprofen, ketoprofen, naproxen, diclofenac, aspirin at pain-relief doses (more than 100 mg a day)… They must not be used from the 6th month of pregnancy (24 weeks), even as a single dose and by any route, including gels or patches on the skin: they can cause serious damage to the baby's heart, lungs and kidneys, and can even cause the baby to die in the womb. Before the 6th month, take an NSAID only if it has been prescribed by a doctor, sometimes with closer monitoring, because it carries a risk of miscarriage, birth defects, kidney problems in the baby and early closure of the ductus arteriosus (a blood vessel the baby needs). Never take one without medical advice; paracetamol should be used first. In France, these medicines carry a “pregnancy” warning symbol on the box.

Low-dose aspirin (100 to 160 mg a day), prescribed by a doctor to prevent pre-eclampsia, is a different situation and is safe in that context (see high blood pressure and pre-eclampsia).

Medicines known to cause birth defects

• Sodium valproate (epilepsy, bipolar disorder): a risk of birth defects of about 10% and a markedly higher risk of autism, as well as of attention deficit hyperactivity disorder (ADHD). It should not be used in women who could become pregnant without a pregnancy prevention programme.
• Isotretinoin and other oral retinoids (acne, psoriasis): absolutely contraindicated, contraception is mandatory.
• Mycophenolate, methotrexate, thalidomide and related drugs, some cancer medicines.
• Vitamin K antagonists (warfarin), replaced by heparins during pregnancy.
• ACE inhibitors and angiotensin receptor blockers (sartans) (high blood pressure): contraindicated in the 2nd and 3rd trimesters, to be switched as soon as a pregnancy is planned or begins.
• Some antibiotics depending on the stage (for example, tetracyclines after the 1st trimester).

This list is not exhaustive: always check with your doctor or pharmacist.

What can I take for common ailments while pregnant?

• Pain and fever: paracetamol is the first-line treatment throughout pregnancy, at the lowest effective dose and for a short time. The French medicines agency (ANSM) recommends it in preference to anti-inflammatories. See fever during pregnancy.
• Nausea and vomiting: several treatments are available on prescription. See first-trimester nausea.
• Heartburn, constipation: some antacids and gentle laxatives can be used, after advice.
• Infections: many antibiotics (notably penicillins and cephalosporins) are well documented in pregnancy.
• Allergy, colds: some antihistamines can be used; oral decongestants (vasoconstrictors) should be avoided.

For health professionals, the French reference centre on teratogenic agents (CRAT) keeps an online database searchable by drug. In France, regional pharmacovigilance centres can also answer questions about an exposure.

Are over-the-counter, herbal remedies and essential oils safe in pregnancy?

“Over-the-counter” or “natural” does not mean “safe in pregnancy”. Without medical advice, avoid:

• over-the-counter medicines containing ibuprofen or aspirin, sometimes combined in cold remedies;
• essential oils, some of which are toxic to the nervous system or can trigger contractions;
• herbal teas and herbal supplements (St John's wort, sage, liquorice, etc.), whose composition and effects are poorly known;
• creams, gels, pessaries or eye drops, which can also pass into the bloodstream.

Your pharmacist is a valuable source of advice: say you are pregnant every time you buy something.

What if I have a chronic illness or take long-term medication?

• Never stop a long-term treatment abruptly when you find out you are pregnant without advice from the doctor who prescribes it: stopping an antiepileptic, an antidepressant or a blood pressure medicine can be dangerous for you and the baby.
• Book an appointment quickly to adjust the drug, dose or timing if needed.
• Ideally, have a preconception appointment: it allows you to change treatment before pregnancy, start folic acid and plan monitoring.
• Appropriate monitoring is put in place: specialist ultrasound scans, blood tests, care for the newborn at birth if needed.

For treatments for mental health conditions, see mental health during pregnancy.

When should I seek urgent help after taking a medicine in pregnancy?

If you took a medicine before you knew you were pregnant, do not panic: most accidental exposures have no consequences. Talk to your doctor soon: they will assess the actual risk, which is often very low. An accidental dose rarely calls for an urgent decision.

However, in France call 15 (SAMU) or 112 (or your local emergency number), or a poison control centre, in case of overdose or if a large amount of medicine has been swallowed. Go to the maternity emergency department where you are registered (Sainte-Félicité Maternity Unit or Clinique Sainte-Thérèse) if, after taking a medicine, you have:

• an allergic reaction (swollen face, difficulty breathing, rash): call 15;
• contractions, bleeding or leaking fluid;
• fewer baby movements;
• taken an anti-inflammatory after 24 weeks, even once, so the baby's wellbeing can be checked.

Frequently asked questions

General information article: it does not replace a medical consultation. In an emergency, call 15 or 112 in France, or your local emergency number.