Medically reviewed by Dr. Arham Shabbir, PhD (Pharmacology), M.Phil (Pharmacology), B.Pharm (RPh)
Updated on
ACOG 2023 • FDA PLLR 2015 • Updated Oct 2026
Drugs Contraindicated in Pregnancy: 20+ Drugs to Avoid by Trimester + Safe Alternatives [FDA 2024 Guide]
Medically reviewed by RxPedia Clinical Team • PharmD, PhD • References: FDA, ACOG, MotherToBaby, Briggs 12th
Direct Answer
⚡ What to Avoid
Main drugs contraindicated in pregnancy are Category X absolute: isotretinoin (Accutane), thalidomide, methotrexate, mycophenolate, leflunomide, warfarin (Coumadin), valproic acid, statins (atorvastatin Lipitor), plus trimester-specific: ACE inhibitors lisinopril, ARBs losartan in 2nd/3rd trimester kidney damage & fetal death, tetracyclines yellow staining teeth, NSAIDs ibuprofen in 3rd trimester closure of ductus arteriosus, aminoglycosides streptomycin ototoxicity. Up to 10% of birth defects linked to teratogenic drug exposure per CDC.
Related: See our complete list of asthma medications — which are safe in pregnancy vs contraindicated overlap, plus drugs contraindicated in diabetes and drugs contraindicated in cardiac patients for comorbidity counseling.
📘 FDA Categories A/B/C/D/X vs New PLLR 2015
🚫 Complete List by Trimester — 20+ Drugs
ACE inhibitors and ARBs that are teratogenic are also contraindicated in cardiac patients with bilateral renal artery stenosis. Valproate and aminoglycosides, teratogenic in pregnancy, also worsen myasthenia gravis. For complete disease-wise safety screening, always cross-check with our Drug Interaction Checker and avoid NSAIDs contraindicated in asthma in 3rd trimester.
✅ Safe Alternatives — Per ACOG
🛠️ Related Clinical Tools & Guides
eGFR Calculator
Check kidney function before ACEi/ARB, NSAIDs, aminoglycosides — dose adjustment in pregnancy.
Open calculator → Complete list of asthma medications — rescue, controller, biologics [GINA 2024]
Which asthma meds are safe in pregnancy? Albuterol considered safe vs contraindicated overlap.
View asthma guide → Drugs contraindicated in diabetes — 15+ to avoid [ADA 2024]
For patients with diabetes + pregnancy — avoid fluoroquinolones, thiazides, steroids without monitoring.
View diabetes guide → Drugs contraindicated in cardiac patients — 12+ to avoid [AHA 2024]
Cardiac + pregnancy overlap — which antihypertensives & statins are contraindicated and safe swaps.
View cardiac guide →
Check kidney function before ACEi/ARB, NSAIDs, aminoglycosides — dose adjustment in pregnancy.
Open calculator → Complete list of asthma medications — rescue, controller, biologics [GINA 2024]
Which asthma meds are safe in pregnancy? Albuterol considered safe vs contraindicated overlap.
View asthma guide → Drugs contraindicated in diabetes — 15+ to avoid [ADA 2024]
For patients with diabetes + pregnancy — avoid fluoroquinolones, thiazides, steroids without monitoring.
View diabetes guide → Drugs contraindicated in cardiac patients — 12+ to avoid [AHA 2024]
Cardiac + pregnancy overlap — which antihypertensives & statins are contraindicated and safe swaps.
View cardiac guide →
🆘 What to Do If Exposed to Contraindicated Drug
- Don't panic — stop the drug and call OB immediately. Note exact drug name, dose, gestational age, duration of exposure.
- Contact MotherToBaby expert: US hotline 866-626-6847 or text 855-999-3525, plus mothertobaby.org fact sheets for every drug listed above. Free confidential counseling per ACOG.
- Do NOT stop antiepileptics abruptly without neurologist — seizure risk to fetus may outweigh teratogenic risk. Valproate needs taper plan to lamotrigine/levetiracetam.
- Enhanced ultrasound timeline: Detailed anatomy scan at 18-20 weeks + fetal echocardiogram if 1st trimester exposure to retinoids, warfarin, lithium, ACEi. For warfarin, consider fetal X-ray for stippling after 20w only if indicated.
- Document & report: FDA MedWatch for adverse pregnancy outcomes, and enroll in pregnancy registries (e.g., North American Antiepileptic Drug Pregnancy Registry 888-233-2334).
- Switch to safe alternative from table above + start high-dose folic acid 4mg daily if on antiepileptics (preconception to 12 weeks).
Timing Matters
Weeks 3-8 (organogenesis) highest risk for major malformations. Weeks 9+ risk shifts to growth & functional deficits (brain, kidneys).
Weeks 3-8 (organogenesis) highest risk for major malformations. Weeks 9+ risk shifts to growth & functional deficits (brain, kidneys).
Isotretinoin iPLEDGE
Requires 2 forms contraception + monthly pregnancy tests. If exposed, risk ~35% major birth defects. Refer to Maternal-Fetal Medicine immediately.
Requires 2 forms contraception + monthly pregnancy tests. If exposed, risk ~35% major birth defects. Refer to Maternal-Fetal Medicine immediately.
🚨 When to Seek Emergency Care
Call 911 or go to ER if:
- Vaginal bleeding, cramping, tissue passage after methotrexate or mycophenolate exposure — possible miscarriage
- Severe headache, visual changes, epigastric pain, swelling after stopping ACEi/ARB — possible preeclampsia worsening
- No fetal movement after NSAID use in 3rd trimester — possible ductus closure / oligohydramnios
- Signs of warfarin bleeding: heavy vaginal bleeding, bruising, abdominal pain
- Seizure, confusion, severe withdrawal after stopping benzodiazepines abruptly
- Signs of gray baby syndrome in newborn after chloramphenicol: ashen color, vomiting, limpness, difficulty breathing
When to talk to doctor promptly (non-emergency)
- You took any Category X or D drug and pregnancy test is positive or missed period
- You have epilepsy, hypertension, or clotting disorder and plan pregnancy — need preconception switch 3 months before
- You were prescribed tetracycline, ciprofloxacin, or NSAID and are in 2nd/3rd trimester
- You need acne treatment and are pregnant — need safe alternative counseling
❓ Frequently Asked Questions
Which antibiotics are contraindicated in pregnancy?
Mainly 4 classes - MCAT mnemonic: Metronidazole (1st trimester controversial), Chloramphenicol (gray baby), Aminoglycosides (ototoxicity/deafness), Tetracyclines (tooth discoloration + bone growth). Safer alternatives are penicillins (amoxicillin), cephalosporins, and azithromycin/erythromycin base. Fluoroquinolones like ciprofloxacin are Category C and generally avoided due to arthropathy risk in animal studies.
Why is warfarin contraindicated in pregnancy?
Warfarin crosses the placenta and causes fetal warfarin syndrome: nasal hypoplasia (flattened nose), stippled epiphyses on X-ray, CNS defects, optic atrophy, intellectual disability, plus bleeding risk. Risk is highest in weeks 6-12. For anticoagulation in pregnancy, heparin and low-molecular-weight heparin (enoxaparin) do NOT cross placenta and are preferred per ACOG. Also see cardiac patients guide for warfarin alternatives.
Are NSAIDs safe in third trimester?
No. FDA strengthened warning in 2020: avoid NSAIDs at ≥20 weeks because they can cause oligohydramnios (low amniotic fluid) from fetal renal dysfunction, and at ≥30 weeks they can cause premature closure of the ductus arteriosus leading to pulmonary hypertension and fetal death. Low-dose aspirin 81mg for preeclampsia prevention is an exception under OB supervision. Also check NSAIDs contraindicated in asthma — overlap.
Is tetracycline safe in pregnancy? Why yellow teeth?
No, contraindicated in 2nd/3rd trimester. Tetracyclines chelate calcium and deposit in calcifying bones and teeth. If taken after 16 weeks when tooth calcification begins, they cause permanent yellow-brown discoloration of deciduous teeth and enamel hypoplasia, plus inhibition of long bone growth. Use penicillin or macrolides instead.
Are ACE inhibitors contraindicated in pregnancy?
Yes in 2nd and 3rd trimester - FDA Boxed warning Category D. ACE inhibitors (lisinopril, enalapril) cause fetopathy: renal failure/dysplasia, oligohydramnios leading to lung hypoplasia and limb contractures, skull hypoplasia, and fetal death. First trimester exposure also increases malformation risk. Stop immediately if pregnancy detected and switch to methyldopa, labetalol, or nifedipine. These are also contraindicated in cardiac patients with bilateral RAS.
Are statins Category X in pregnancy?
Historically yes - all statins were FDA Category X because cholesterol is essential for fetal development. In 2021 FDA removed strongest warning and allows continued use in very high-risk patients (e.g., homozygous familial hypercholesterolemia) after shared decision, but routine use remains contraindicated. ACOG still recommends stopping statins when pregnancy is planned or detected. Check statins worsening myasthenia gravis as well.
Which painkiller is safe in pregnancy?
Acetaminophen (Tylenol) is considered safest per ACOG and CDC - ≤3g/day total from all sources, shortest duration. Avoid ibuprofen/naproxen in 3rd trimester (≥20w per FDA) and high-dose aspirin. For severe pain, limited opioids under supervision may be used short-term, but discuss dependence/withdrawal risks. Always cross-check with Drug Interaction Checker.
📖 References — Harvard Style
- FDA (2015) Pregnancy and Lactation Labeling Rule (PLLR) Final Rule. Federal Register 79 FR 72064. U.S. Food & Drug Administration.
- ACOG (2023) Clinical Guidance for Medications in Pregnancy. Practice Bulletin No. 233, Reaffirmed 2023. American College of Obstetricians and Gynecologists.
- EMA PRAC (2018) Retinoids teratogenic risk - oral retinoids contraindicated in pregnancy. EMA/2018/231. European Medicines Agency.
- Briggs, G.G., Freeman, R.K., Towers, C.V. and Forinash, A.B. (2022) Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk. 12th ed. Philadelphia: Wolters Kluwer.
- MotherToBaby (2023) Fact Sheets Expert - Isotretinoin, Warfarin, Valproic Acid, ACE inhibitors. Organization of Teratology Information Specialists.
- BNS Institute (2023) Safe and Unsafe Drug Use During Pregnancy - MCAT mnemonic MCAT. Journal of Medical Education.
- WikiLectures (2023) Drugs in pregnancy - trimester split and teratogenic mechanisms.
- Renal and Urology News (2022) Drugs Contraindicated in Pregnancy - system list and nephrotoxicity considerations.
- PMC Review (2020) Teratogenic Effects of Leflunomide, Accutane, Thalidomide, Warfarin, Tetracycline, ACE inhibitors. Cureus 12(7).
- ObGyn Key (2023) Medications Contraindicated in Pregnancy Table 20.2. In: Clinical Obstetrics.
- CDC (2023) Treating for Two: Medications and Pregnancy - 10% birth defects linked to exposures. Centers for Disease Control.
- FDA (2022) Isotretinoin iPLEDGE REMS - Risk Evaluation and Mitigation Strategy to prevent pregnancy exposure.
- FDA (2015, updated 2020) FDA strengthens warning NSAIDs and fetal ductus arteriosus / oligohydramnios after 20 weeks.
- NDA Uganda (2023) Teratogenic Drugs and Agents - warfarin bleeding and fetal syndrome review. National Drug Authority.
- WHO (2023) Essential Medicines - pregnancy considerations and safe alternatives list. World Health Organization Model Formulary.
Disclaimer: This guide is for educational purposes and does not replace medical advice. Always consult your obstetrician, maternal-fetal medicine specialist, and pharmacist before starting or stopping any medication in pregnancy. In emergency call 911. Last updated Oct 2026.
RxPedia • ACOG 2023 • FDA PLLR • Evidence-based drug safety • Updated Oct 2026
💊 Planning pregnancy? For women planning pregnancy, CDC recommends 400-800mcg folic acid daily, but if you have MTHFR variant, which folate is better methylfolate vs folic acid matters for absorption. Check your dose with our folic acid dosage calculator.
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