Pregnancy changes a lot of everyday habits, and a hot tub soak is one of them. The answer from the sources is more cautious than for most hot tub questions.
This article sets out what U.S. safety guidance and the main study say. It sits under our overview of hot tub benefits. It is general information, not medical advice: your obstetric provider is the one to ask.
Short answer: Cleveland Clinic says to avoid hot tubs while pregnant, because raising your body temperature could harm the fetus, especially in the first trimester. Older CPSC guidance sets a 100°F maximum in pregnancy. A 1992 study linked early-pregnancy hot tub use to a higher risk of neural tube defects.
What the guidance says
The two sources differ in how strict they are:
| Source | Guidance |
|---|---|
| Cleveland Clinic, 2025 | Avoid hot tubs if pregnant; raising body temperature could harm the fetus, especially in the first trimester |
| CPSC, 1979 | Pregnant women should stick to a 100°F maximum; water above 102°F can cause fetal damage in the first 3 months |
The CPSC release is from 1979. Cleveland Clinic’s article is from November 2025, so it is the more current of the two.
What the 1992 study found
A study in JAMA followed 23,491 women having prenatal screening, mostly in private obstetric practices in New England. It asked about heat exposure from hot tubs, saunas, fever, and electric blankets in early pregnancy.
| Exposure in early pregnancy | Adjusted relative risk of neural tube defects |
|---|---|
| Hot tub | 2.8 (95% CI 1.2 to 6.5) |
| Sauna | 1.8 (confidence interval included 1) |
| Fever | 1.8 (confidence interval included 1) |
| Electric blanket | 1.2 (not materially associated) |
The authors wrote that hot tub exposure “appeared to have the strongest effect of any single heat exposure.” Women exposed to two kinds of heat had a relative risk of 6.2.
Here’s what the headline won’t tell you. A relative risk compares groups; it doesn’t say how likely a defect is in one pregnancy, and the abstract doesn’t give that figure. It is also one observational study, so it shows an association, not proof that the hot tub caused the defects.
Why the first trimester comes up
Both sources point to early pregnancy. CPSC names “the first three months.” Cleveland Clinic says the risk is especially in the first trimester. The JAMA study looked at heat exposure in early pregnancy.
Questions to ask your provider
- Is any hot tub use OK for me, and at what water temperature?
- Does it matter how far along I am?
- What about a warm bath instead?
Bottom line: the most current guidance here says to skip the hot tub while pregnant, and the older CPSC rule caps the water at 100°F. Talk to your provider before you soak. For hot tub health claims more broadly, see the hot tub benefits overview linked above.
Sources
- Cleveland Clinic, “Soak It In: How Hot Tubs Can Boost Your Health,” November 17, 2025: health.clevelandclinic.org
- U.S. Consumer Product Safety Commission, “CPSC Warns Of Hot Tub Temperatures,” release 79-071, December 31, 1979: cpsc.gov
- Milunsky A, et al., “Maternal heat exposure and neural tube defects,” JAMA, 1992 (abstract): pubmed.ncbi.nlm.nih.gov