Sauna or hot tub while trying to conceive: what the evidence says for both partners
Neural tube defects happen in the first few weeks of pregnancy, often before a positive test. For the partner producing sperm, regular heat lowers sperm count, and it reverses. Here is what that means for each of you.
Short answer: For the person trying to get pregnant, heat matters most once you might already be pregnant. The CDC says neural tube defects happen in the first few weeks of pregnancy, often before you know, and lists overheating or fever among the factors that might raise the chance of spina bifida. ACOG says it’s best not to use a sauna or hot tub early in pregnancy. The cautious reading is to skip hot tubs and saunas from ovulation until you know you are not pregnant. For the partner producing sperm, regular heat lowers sperm count and motility, and it reverses: in a 2013 study, every change had reversed six months after stopping.
Trying to conceive turns a sauna or a hot tub into two separate questions. One is about a pregnancy that may already have started without a positive test. The other is about sperm, which are sensitive to heat in their own way.
This guide takes them in turn: what the official sources say, what the studies found, and a cautious plan for each partner.
This is general information, not medical advice. If you are working with a fertility doctor, their instructions for your cycle come first.
Why the weeks before a positive test matter
The timing problem is simple. The CDC says neural tube defects, serious birth defects of the brain and spine, “happen in the first few weeks of pregnancy, often before you know you are pregnant.”
Heat is on the list of possible contributors. The CDC’s page on spina bifida names “overheating or fever” among the factors research has reported might increase the chance of having a baby with spina bifida.
And the guidance on saunas and hot tubs is about exactly those weeks. Asked “Can I use a sauna or hot tub early in pregnancy?”, ACOG answers: “It’s best not to.” When you are trying to conceive, any cycle after ovulation could be early pregnancy.
What the pregnancy studies found
The studies are observational, so they show links rather than proof, and the links sit in early pregnancy.
A 1992 study in JAMA followed 23,491 women and found that hot tub use in early pregnancy was linked with about 2.8 times the risk of a neural tube defect, the strongest effect of any heat source it measured.
A Kaiser Permanente study of 1,063 pregnant women found hot tub or whirlpool use after conception linked with twice the risk of miscarriage, and the risk rose with more frequent use and with use in the earliest weeks.
The absolute risks are small, and our guide to hot tubs in pregnancy puts them in context. Small is not zero, though, and these are weeks when you cannot yet know.
A cautious plan if you are trying to get pregnant
No official body gives a rule for trying to conceive, so this is our reading of the guidance above, not a rule from it.
- The first half of your cycle, before ovulation, is not the time the studies worry about, because there is no pregnancy yet in that cycle.
- From ovulation until your period or a negative test, treat yourself as possibly pregnant and skip hot tubs and saunas, as ACOG advises for early pregnancy.
- If you use heat at all, keep it short and cool. The Consumer Product Safety Commission’s hot tub rule for pregnancy is water no hotter than 100°F, and getting out when you feel hot is the signal to act on.
- Skip heat with a fever, which already raises your core temperature.
If tracking ovulation is hard, the simplest version is to pause regular hot tub and sauna use while you are trying, and to ask your doctor whether that is needed for you.
For the partner producing sperm
Here the evidence is about sperm, not pregnancy, and the effect is reversible.
In a 2013 study in Human Reproduction, 10 men with normal semen used a Finnish sauna twice a week for three months, 15 minutes at 80 to 90°C. Sperm count and motility fell sharply, with no significant change in sex hormones, and every change had completely reversed six months after they stopped.
Hot tubs show the same pattern. In a 2007 study of 11 infertile men who regularly used hot tubs or hot baths, five improved strongly after stopping, with total motile sperm count up by an average of 491%.
So pausing regular heat several months before you start trying is the useful move, not stopping the week before. Our guide to sauna, hot tubs and sperm count covers both studies in full.
During IVF or other fertility treatment
We searched PubMed on 6 October 2026 and found no study of ordinary sauna or hot tub use during IVF treatment. That means there is no evidence either way, not that heat is fine.
Your clinic’s instructions come first. If they have not mentioned saunas or hot tubs, ask, and tell them about any regular heat habit for either partner, since the sperm studies above are part of the picture.
Trying to conceive and heat at a glance
| Question | What the sources say |
|---|---|
| When birth defects form | Neural tube defects happen in the first few weeks, often before you know (CDC) |
| Heat as a factor | Overheating or fever may increase the chance of spina bifida (CDC) |
| Early pregnancy | ”It’s best not to” use a sauna or hot tub (ACOG) |
| After ovulation | Our reading: treat as possibly pregnant and skip the heat |
| Water temperature in pregnancy | 100°F maximum (CPSC) |
| Sperm | Twice-weekly sauna for 3 months cut count and motility; reversed 6 months after stopping |
| IVF | No study found; follow your clinic |
Questions to take to your doctor
- Should I pause saunas or hot tubs while we are trying, or only after ovulation?
- Is there a water temperature or time limit you would be comfortable with for me?
- How long before trying should my partner stop regular sauna or hot tub use?
- During treatment, are there days when heat matters more?
FAQ: saunas, hot tubs and trying to conceive
Can I use a sauna while trying to conceive? Before ovulation, the pregnancy concern does not apply yet. From ovulation until you know you are not pregnant, the cautious reading of ACOG’s advice for early pregnancy is to skip it, since neural tube defects happen in the first few weeks, often before a positive test.
Can I use a hot tub during the two-week wait? The cautious answer is no. Studies linked hot tub use in early pregnancy with neural tube defects and miscarriage, and in the two-week wait you cannot yet know whether you are pregnant.
Does a sauna affect sperm when trying to conceive? Regular use can. Twice-weekly sauna sessions for three months strongly reduced sperm count and motility in a 2013 study, and every change had reversed six months after stopping.
How long before trying should my partner stop using a sauna or hot tub? In the 2013 sauna study, recovery was complete six months after stopping, so pausing several months ahead is the cautious plan. A doctor can advise on your own timing.
Can I use a sauna during IVF? We found no study of ordinary sauna or hot tub use during IVF, so there is no evidence either way. Ask your clinic and follow its instructions.
The bottom line on heat while trying to conceive
For the person trying to get pregnant, the risk window is early pregnancy, and it starts before a positive test. Skipping hot tubs and saunas from ovulation until you know is a small price for that uncertainty.
For the partner producing sperm, regular heat lowers count and motility and the effect reverses, so pause it months ahead rather than days. Either way, an occasional sauna earlier in the cycle is not the thing to worry about.