Acetaminophen
MedicationTylenol
Also called · 1 name▾▴
paracetamol
Analgesic and fever reducer
Research strength: 4 / 5
MotherToBaby reports that, at recommended doses, acetaminophen has not been shown to increase the chance of birth defects. A US study of 16,110 children (Feldkamp 2010) found no increased risk of any birth defect with first-trimester use. MotherToBaby also notes that one study found no increased chance of miscarriage, no matter when it was taken or for how long. ACOG (Sept 2025) and SMFM call it the first-line medicine for pain and fever in pregnancy. Health agencies disagree on whether pregnant people should cut back on acetaminophen because of possible links to autism and ADHD. See the full research for both sides. Ask your provider about your situation.
Last reviewed: 2026-10-14
Sources
- MotherToBaby: Acetaminophen (Paracetamol) fact sheetTeratology service
- ACOG Practice Advisory: Acetaminophen Use in Pregnancy and Neurodevelopmental OutcomesProfessional society
- SMFM Statement: Acetaminophen use during pregnancy (endorsed by ACOG)Professional society
- Feldkamp et al., Obstet Gynecol 2010 (US National Birth Defects Prevention Study)US government
- CDC: Medicine and Pregnancy, An OverviewUS government
Research strength: 4 / 5
MotherToBaby reports that a review of over 36,000 pregnancies did not find a link to preterm delivery or low birth weight. A study of over 24,000 pregnancies did report more pregnancy problems, but it did not look at why people were taking acetaminophen. ACOG and SMFM call it the first-line medicine for pain and fever in pregnancy, at the lowest effective dose for the shortest time needed. Health agencies disagree on whether pregnant people should cut back on acetaminophen because of possible links to autism and ADHD. See the full research for both sides. Ask your provider about your situation.
Last reviewed: 2026-10-14
Sources
- MotherToBaby: Acetaminophen (Paracetamol) fact sheetTeratology service
- ACOG Practice Advisory: Acetaminophen Use in Pregnancy and Neurodevelopmental OutcomesProfessional society
- SMFM Statement: Acetaminophen use during pregnancy (endorsed by ACOG)Professional society
- Castro et al., Expert Opin Drug Saf 2022 (meta-analysis)US government
- CDC: Medicine and Pregnancy, An OverviewUS government
Research strength: 4 / 5
One UK study (Golding 2020) found a weak link between use at 18 to 32 weeks and mother-reported behavior problems at about 3.5 to 4 years. It found few links after age 7 to 8, and MotherToBaby says it is not clear if this was due to acetaminophen or other factors. ACOG and SMFM call it the first-line medicine for pain and fever in pregnancy. Health agencies disagree on whether pregnant people should cut back on acetaminophen because of possible links to autism and ADHD. See the full research for both sides. Ask your provider about your situation.
Last reviewed: 2026-10-14
Sources
- MotherToBaby: Acetaminophen (Paracetamol) fact sheetTeratology service
- ACOG Practice Advisory: Acetaminophen Use in Pregnancy and Neurodevelopmental OutcomesProfessional society
- SMFM Statement: Acetaminophen use during pregnancy (endorsed by ACOG)Professional society
- Golding et al., Paediatr Perinat Epidemiol 2020 (UK ALSPAC)US government
- CDC: Medicine and Pregnancy, An OverviewUS government
Acetaminophen — Breastfeeding
Research strength: 4 / 5
According to LactMed (NIH), acetaminophen is a good choice for pain relief and fever reduction in nursing mothers. The amount in breast milk is much less than doses usually given to infants, and side effects in breastfed babies appear to be rare. The UK NHS Specialist Pharmacy Service also calls it the pain reliever of choice while breastfeeding, while noting there is very little published evidence. These sources base this on small studies of drug levels in milk and infant follow-up, plus long use. Ask your provider about your situation.
Last reviewed: 2026-10-14
Sources
- LactMed (NIH): AcetaminophenUS government
- NHS Specialist Pharmacy Service: Using paracetamol during breastfeedingUK government
- MotherToBaby: Acetaminophen (Paracetamol) fact sheetTeratology service
Pregnancy
Birth defects: a US case-control study (Feldkamp 2010; 11,610 children with birth defects, 4,500 without) found first-trimester use of plain acetaminophen was not linked to any birth defect. Miscarriage: MotherToBaby cites a study that found no increased chance of miscarriage, no matter when or how long it was used. Preterm birth and birth weight: a 2022 meta-analysis of 6 studies (Castro 2022) found no increased risk of preterm birth (RR 0.97). MotherToBaby notes one study of over 24,000 pregnancies that did find more problems but did not account for why people took it. Autism and ADHD: a Norwegian study (Brandlistuen 2013; 48,631 children) linked use for more than 28 days to poorer motor and behavior scores at age 3. A UK study (Golding 2020) linked use at 18 to 32 weeks to behavior problems at about 3.5 to 4 years, with few links after age 7 to 8. A 2025 review of 46 studies (Prada 2025) counted 27 with positive links. Studies that compared brothers and sisters in the same family found no link: Sweden (Ahlqvist 2024; 2,480,797 children, 185,909 exposed; HR 0.98 for autism) and Hong Kong (Luo 2026; HR 1.00 for autism, 1.01 for ADHD). The Hong Kong study also found the same links with use before pregnancy, which points to family factors rather than the medicine. Overdose: MotherToBaby reports that too much acetaminophen can cause liver damage, kidney damage and anemia in adults, and has been reported to cause the same problems in the fetus.
Breastfeeding
LactMed reports that after a single 650 mg dose in 12 nursing mothers, peak milk levels were 10 to 15 mg/L and the drug was undetectable 12 hours later. A baby would get about 0.14% of the mother's dose by weight. In a telephone follow-up, mothers reported no side effects in 43 exposed infants. One 2-month-old had a rash that was probably caused by acetaminophen in milk. LactMed also reports that giving acetaminophen with ibuprofen on a fixed schedule for 24 hours after vaginal delivery appears to increase breastfeeding rates. NHS SPS calls it the pain reliever of choice while breastfeeding and notes very little published evidence.
Acetaminophen (also called paracetamol) is the active ingredient in Tylenol. MotherToBaby notes it is also in many combination cold, flu and pain products, so labels need checking to keep the total under the daily limit.
What was tested
Human studies include large population registries (Sweden, Norway, Hong Kong, US), a US birth defects case-control study, a meta-analysis on birth outcomes, and small breast milk level studies. Most pregnancy studies are observational, meaning they look at what people already took. No randomized trials test long-term child outcomes.
Should pregnant people cut back on acetaminophen because of possible autism and ADHD links?
- Source A says
- The CDC (updated Sept 2026) says pregnant women should consider avoiding acetaminophen as a precaution, while stating a direct causal link has not been established. The FDA (Sept 2025) asked doctors to consider minimizing use for routine low-grade fevers. A 2025 review found most of 46 studies reported a link. (CDC: Medicine and Pregnancy, An Overview, FDA: Notice to Physicians on the Use of Acetaminophen During Pregnancy, Prada et al., Environmental Health 2025 (Navigation Guide review))
- Source B says
- ACOG, SMFM and the European Medicines Agency say acetaminophen remains the first-line choice for pain and fever in pregnancy, and that the weight of evidence does not support a causal link. Two large sibling-comparison studies found no link. (ACOG Practice Advisory: Acetaminophen Use in Pregnancy and Neurodevelopmental Outcomes, SMFM Statement: Acetaminophen use during pregnancy (endorsed by ACOG), European Medicines Agency: Use of paracetamol during pregnancy unchanged in the EU, Ahlqvist et al., JAMA 2024 (Sweden, sibling comparison), Luo et al., JAMA Internal Medicine 2026 (Hong Kong, sibling-matched))
- Why they differ
- Studies that compare different families tend to find small links. Studies that compare siblings in the same family, which control for shared genes and home life, tend to find none. Groups also weigh caution differently when causation is not established. One author of the 2025 review disclosed serving as an expert witness for plaintiffs in acetaminophen lawsuits.
- Other sources
- The UK MHRA (23 Sept 2025) said there is no evidence that paracetamol in pregnancy causes autism. WHO (24 Sept 2025) said there is no conclusive scientific evidence of a link. (UK MHRA Drug Safety Update: Paracetamol and pregnancy, WHO statement on autism-related issues)
- What the evidence shows overall
- The largest studies that control for family factors found no link, and most major medical groups still list acetaminophen as the first choice for pain and fever in pregnancy. US agencies now advise caution, especially for low-grade fevers, without saying it causes harm. The evidence is still being studied.
- ACOG describes use at the lowest effective dose for the shortest necessary time, in consultation with an obstetric care professional, as consistent with best practice. (ACOG)
- The European Medicines Agency says to use it at the lowest effective dose, for the shortest possible time and as infrequently as possible. (European Medicines Agency)
- The CDC says low-grade fevers generally do not require any medication, while high fevers have been linked to birth defects. (CDC)
- MotherToBaby suggests checking labels of combination products so the total amount over 24 hours does not go above what is recommended. (MotherToBaby)
General research, not specific to pregnancy.
The Tylenol label warns about liver damage at high doses for everyone, pregnant or not.
- The label warns that severe liver damage may occur if an adult takes more than 4,000 mg in 24 hours, takes it with other acetaminophen products, or has 3 or more alcoholic drinks a day while using it. (DailyMed: Tylenol Regular Strength tablet label (Kenvue))
- The label also warns that acetaminophen may cause severe skin reactions. (DailyMed: Tylenol Regular Strength tablet label (Kenvue))
- MotherToBaby: Acetaminophen (Paracetamol) fact sheetTeratology serviceSecondaryPage dated 2025-10-01
- LactMed (NIH): AcetaminophenUS governmentSecondaryPage dated 2026-04-15
- ACOG Practice Advisory: Acetaminophen Use in Pregnancy and Neurodevelopmental OutcomesProfessional societySecondaryPage dated 2025-09-01
- SMFM Statement: Acetaminophen use during pregnancy (endorsed by ACOG)Professional societySecondaryIndependent check
- European Medicines Agency: Use of paracetamol during pregnancy unchanged in the EUEU agencySecondaryPage dated 2026-01-20Independent checkEuropean guidance
- CDC: Medicine and Pregnancy, An OverviewUS governmentSecondaryPage dated 2026-09-17
- FDA: Notice to Physicians on the Use of Acetaminophen During PregnancyUS governmentSecondaryPage dated 2025-09-01
- NHS Specialist Pharmacy Service: Using paracetamol during breastfeedingUK governmentSecondaryPage dated 2024-10-11Independent check
- DailyMed: Tylenol Regular Strength tablet label (Kenvue)Drug company labelTertiaryPage dated 2026-05-28
- UK MHRA Drug Safety Update: Paracetamol and pregnancyUK governmentSecondaryPage dated 2025-09-23
- WHO statement on autism-related issuesInternational agencySecondaryPage dated 2025-09-24
- Ahlqvist et al., JAMA 2024 (Sweden, sibling comparison)US governmentPrimaryIndependent check
- Luo et al., JAMA Internal Medicine 2026 (Hong Kong, sibling-matched)US governmentPrimaryIndependent check
- Prada et al., Environmental Health 2025 (Navigation Guide review)US governmentPrimary
- Brandlistuen et al., Int J Epidemiol 2013 (Norway, sibling-controlled)US governmentPrimaryIndependent check
- Golding et al., Paediatr Perinat Epidemiol 2020 (UK ALSPAC)US governmentPrimaryIndependent check
- Feldkamp et al., Obstet Gynecol 2010 (US National Birth Defects Prevention Study)US governmentPrimaryIndependent check
- Castro et al., Expert Opin Drug Saf 2022 (meta-analysis)US governmentPrimaryIndependent check
Last reviewed 2026-10-14
Independent check 2026-10-14
Not yet clinician-reviewed
Ask your provider about your situation.