Medicines and prescriptions
What Is Fetal Toxicity? Pregnancy Warnings on Labels
Fetal toxicity · say it: FEE-tul tok-SIS-ih-teeAlso written: embryo-fetal toxicity, foetal toxicity, fetotoxicity, harm to the unborn baby, Fetotoxicity, fetal toxicity
Short answer
Fetal toxicity means a medicine or substance can harm an unborn baby during pregnancy. Some medicine labels carry this warning in a box.
What it means
Fetal toxicity means harm to a developing baby in the womb from something the mother is exposed to, such as a medicine. Harm can include problems with growth, organ development or function, miscarriage, or problems after birth. The risk often depends on the medicine, the dose and the stage of pregnancy.
Labels for some medicines carry a fetal toxicity warning, sometimes as a boxed warning. Examples include ACE inhibitors and angiotensin II receptor blockers (especially later in pregnancy), some acne, cancer and anti-seizure medicines, and others. The label usually says to stop the medicine as soon as pregnancy is detected, or to use contraception during treatment. The warning is telling you to talk to your doctor before trying for a baby and to contact them promptly if you become pregnant; do not just stop a medicine without advice, as that can also carry risks.
Fetal toxicity is a broad term. 'Teratogenic' usually refers to causing birth defects as the baby forms, while fetal toxicity can include harm at any stage of pregnancy.
Where you may see it
- Boxed warnings on ACE inhibitor and ARB labels
- Pregnancy sections of prescribing information
- Medication Guides and pregnancy prevention leaflets
📄 How it looks on a report
WARNING: FETAL TOXICITY. When pregnancy is detected, discontinue as soon as possible. Drugs that act on the renin-angiotensin system can cause injury and death to the developing fetus.
🙅 What it does not mean
- It does not mean every pregnancy exposed to the medicine will be harmed.
- It does not mean you should stop suddenly without speaking to your doctor; get advice quickly.
- It does not mean the medicine is unsuitable for people who cannot become pregnant.
🎯 Check yourself
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🗒️ Questions to ask your doctor
🧾 Reports where you will see “Fetal toxicity”
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💊 Medicines whose labels mention “Fetal toxicity”
Plain-English explanations of each medicine, from its official FDA label.
- Enalapril
An angiotensin-converting enzyme (ACE) inhibitor
- Levofloxacin
an antibiotic of the fluoroquinolone type
- Lisinopril
an angiotensin converting enzyme (ACE) inhibitor, a type of medicine that helps relax blood vessels to lower blood pressure
- Losartan Potassium
an angiotensin II receptor blocker (ARB), a type of medicine used to lower blood pressure
- Methotrexate
A dihydrofolate reductase inhibitor, a type of medicine that works against folate (a vitamin-like substance cells use to grow and divide). The FDA pharmacologic class is not listed on the label.
- Valsartan
An angiotensin II receptor blocker (ARB), a type of medicine used to treat high blood pressure and certain heart conditions
🔗 Read more from trusted sources
- “Fetal toxicity” on MedlinePlus ↗
US National Library of Medicine
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