If you're pregnant or planning to become pregnant, you've likely encountered conflicting wellness advice. One guideline that stands out—and matters profoundly—comes from the American College of Obstetricians and Gynecologists (ACOG): pregnant women should avoid saunas, hot tubs, and other forms of prolonged heat exposure. This recommendation applies to all sauna types, including infrared saunas, despite their growing popularity in wellness circles.
At Peak Saunas, we believe in evidence-based wellness and full transparency. While we're passionate about infrared sauna benefits for many populations, supporting maternal and fetal health is paramount. This guide explains why ACOG issued this guidance, what the science shows, and what pregnant women can safely do to maintain wellness during pregnancy.
Why ACOG Recommends Against Saunas During Pregnancy
The American College of Obstetricians and Gynecologists' caution around sauna use during pregnancy centers on one critical physiological fact: elevated maternal core body temperature, particularly during the first trimester, may increase the risk of neural tube defects and other adverse pregnancy outcomes.
The First Trimester Vulnerability Window
The first trimester—roughly weeks 1 through 12 of pregnancy—is when the fetal neural tube is forming and closing. This is the period of most rapid organogenesis. During this critical window, maternal fever or sustained heat elevation has been associated in epidemiological studies with increased risk of birth defects, including neural tube defects (spina bifida and anencephaly) and other congenital anomalies.
The concern is not incidental warmth—it's sustained elevation of core body temperature above approximately 38.5°C (101.3°F).
Saunas and hot tubs achieve and maintain exactly this level of heat stress. An infrared sauna operating at typical consumer temperatures (typically 40–65°C / 104–150°F in the cabin) will raise your core body temperature within minutes. A traditional sauna at 70–90°C (158–194°F) does so even more rapidly. Both create the exact thermal conditions ACOG warns against.
The Mechanism: Heat Stress and Fetal Risk
When a pregnant person enters a sauna—infrared or traditional—core body temperature rises. This is not a hypothetical concern; it's measurable physiology. Research on whole-body hyperthermia shows that even single acute heat exposures can elevate core temperature by 0.8–1.0°C or more. In a pregnant person, this elevation crosses the threshold of concern.
Why? The developing embryo and fetus:
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Cannot thermoregulate independently and relies entirely on the maternal core temperature gradient.
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Is most vulnerable to heat stress during organogenesis, when tissues are differentiating and forming.
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Lacks the physiological buffers that protect adults from transient heat stress.
ACOG's recommendation is thus a precautionary principle applied to a population in which the margin for safety is zero.
What the Evidence Says: Heat Exposure and Pregnancy Outcomes
While high-quality randomized controlled trials on sauna use in pregnancy are ethically impossible to conduct (no researcher would randomize pregnant women to heat exposure and measure fetal outcomes), observational epidemiology and case reports consistently support ACOG's stance.
Maternal Fever and Birth Defects
Large epidemiological studies have shown that maternal fever during the first trimester—whether from infection or other causes—is associated with increased neural tube defect risk. The critical threshold appears to be sustained elevation above 38.5°C for more than brief periods.
A sauna session of even 15–20 minutes in a 50°C infrared cabin or a 75°C traditional sauna will elevate core temperature well into this range. Unlike fever, which is often accompanied by inflammation and infection signals, sauna-induced hyperthermia is a "clean" thermal stress—but the fetal nervous system does not distinguish between the two. Heat is heat. infrared sauna for inflammation and pain
Hot Tub and Sauna Use in Pregnancy: Observational Data
Smaller epidemiological studies have specifically examined sauna and hot tub use during early pregnancy. While the literature is not extensive, the consistent message is one of caution: women who used hot tubs in early pregnancy show a trend toward increased birth defect risk in some studies, and ACOG extrapolates this concern to all forms of prolonged heat exposure, including saunas.
Why Traditional and Infrared Saunas Are Both Included
A common misconception is that infrared saunas—which operate at lower air temperatures than traditional Finnish saunas—are safer in pregnancy because the cabin temperature is lower. This is a false reassurance.
What matters is not cabin air temperature; it is core body temperature. Infrared saunas deliver radiant heat directly to the body, bypassing the air. Research on infrared sauna physiology shows that core temperature rises robustly and comparably to traditional saunas when sessions are matched for duration. A 2022 study found that core temperature increased significantly during infrared sauna exposure in healthy women—the same mechanism that would elevate fetal risk.
ACOG's guidance applies equally to infrared saunas. Neither type is considered safe during pregnancy.
Second and Third Trimester Considerations
While ACOG's strongest warnings apply to the first trimester, caution around sauna use is recommended throughout pregnancy. Here's why:
Later Pregnancy Risks
Even after the neural tube has closed (typically by week 12), sustained maternal hyperthermia poses risks:
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Preterm labor: Elevated core temperature has been associated with uterine contractions.
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Placental function: The placenta's ability to exchange heat and gases may be compromised by sustained maternal hyperthermia.
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Maternal dehydration: Saunas cause profuse sweating. Pregnancy already increases fluid demands; a sauna session risks dangerous dehydration, which can trigger contractions or reduce placental blood flow.
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Heat-stress proteins and fetal stress: Acute hyperthermia triggers heat-shock protein responses that, while protective in non-pregnant adults, may signal fetal distress.
Gestational Diabetes and Heat Stress
Pregnancy alters glucose metabolism. Interestingly, recent research suggests acute infrared sauna exposure may worsen postprandial glucose control. A 2024 study found that a single 40-minute infrared sauna session increased postprandial glucose area-under-the-curve in adults with type 2 diabetes compared to thermoneutral control. While this study was not in pregnant women, it raises a flag: if infrared sauna impairs glucose tolerance even in non-pregnant adults with diabetes, the metabolic stress on a pregnant person—who is already managing gestational changes in insulin sensitivity—could be problematic.
Safer Wellness Alternatives for Pregnant Women
The good news: avoiding saunas during pregnancy does not mean forgoing wellness. Many evidence-based, safe practices support maternal and fetal health.
Warm (Not Hot) Baths
A warm bath at approximately 36–37°C (96–99°F)—body temperature or slightly above—is safe. The key difference from a sauna is duration and intensity. A 15–20 minute warm bath does not elevate core temperature the way a sauna does. The buoyancy also relieves joint pressure, making warm baths excellent for pregnancy-related discomfort.
Gentle Movement and Exercise
Low-impact exercise—walking, swimming in non-heated pools, prenatal yoga, and stationary cycling—has strong evidence supporting safety and benefit in pregnancy. These activities improve cardiovascular fitness, mood, and musculoskeletal health without the thermal risk. infrared sauna cardiovascular health guide
Stress Reduction and Relaxation
Pregnancy can be stressful. Instead of heat-based relaxation, consider:
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Prenatal massage (performed by a certified practitioner familiar with pregnancy anatomy)
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Guided meditation and breathing exercises (no equipment needed; strong evidence for anxiety reduction)
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Acupuncture (growing evidence for pregnancy-related musculoskeletal and nausea support, when provided by licensed practitioners)
Hydration and Nutritional Support
Optimal hydration, adequate protein, and prenatal vitamin supplementation—including folic acid to support neural tube closure—are foundational and far more impactful than any sauna regimen.
Professional Guidance
Every pregnancy is unique. Obstetric care providers can offer personalized recommendations based on individual health status, pregnancy complications, and goals. This is the safest, most evidence-based approach.
What About Postpartum and Breastfeeding?
Once pregnancy is over, can women return to saunas?
Postpartum Period (First 6 Weeks)
The immediate postpartum period involves significant fluid shifts, potential dehydration, and cardiovascular adaptation. ACOG does not explicitly restrict sauna use postpartum, but practical caution is wise. A woman who has experienced significant blood loss or is managing postpartum complications should avoid saunas until cleared by her provider.
For uncomplicated vaginal or cesarean delivery, waiting at least 4–6 weeks before resuming sauna use—and being very cautious about hydration—is reasonable. The postpartum period is not the time to introduce new heat stress.
Breastfeeding
Sauna use is generally considered compatible with breastfeeding, provided the person remains well-hydrated. Heat does not substantially alter breast milk composition or safety. However, extreme dehydration could reduce milk supply, so adequate fluid intake is critical.
Start conservatively: a short, mild infrared session (15 minutes at 45°C) with water intake before and after, rather than a full-intensity 40-minute session.
The Bottom Line: Why Peak Saunas Supports ACOG's Guidance
At Peak Saunas, we believe in honest conversation about where sauna therapy excels—and where it does not belong.
For non-pregnant adults, growing evidence supports infrared and traditional sauna use for cardiovascular health, relaxation, and recovery. Studies on Finnish sauna bathing have shown associations with reduced cardiovascular mortality and hypertension risk. Far-infrared sauna research, while smaller, suggests benefits for select populations including those with heart failure and certain musculoskeletal conditions.
But pregnancy is different. The stakes are higher. A single sauna session poses no guaranteed harm, but the risk—however small—of neural tube defects and other heat-related fetal complications is not one a pregnant person should accept when evidence-based, safe alternatives exist.
ACOG's guidance is not overly cautious; it is proportionate. Pregnant women should avoid saunas, hot tubs, and prolonged heat exposure. This applies to infrared saunas equally to traditional saunas.
If you are pregnant and have questions about thermal exposure, heat therapy, or wellness during pregnancy, the most important step is a conversation with your obstetrician or midwife. They can assess your individual circumstances and provide guidance tailored to your health and pregnancy.
For everyone else, sauna wellness awaits—but for nine months, prioritizing maternal and fetal safety comes first.
Frequently Asked Questions
Q: Is a brief infrared sauna session (5–10 minutes) safe in early pregnancy?
A: No. ACOG does not provide a "safe threshold" for sauna use in pregnancy, because the physiology is straightforward: any sustained sauna exposure will elevate core body temperature into the range associated with fetal risk. Even a short session in an infrared sauna can raise core temperature 0.5–1.0°C within minutes. The safest approach is avoidance during pregnancy.
Q: What if I didn't know I was pregnant and used a sauna once?
A: A single, brief sauna exposure before knowing about pregnancy is not grounds for panic. While the evidence suggests consistent or repeated heat stress poses risk, an isolated exposure—especially if brief—is far less concerning. That said, it is worth mentioning to your obstetric care provider at your first appointment so they can document timing and address any anxiety. Do not use saunas again once pregnancy is confirmed.
Q: Can I use a sauna in the third trimester if I'm careful and stay hydrated?
A: ACOG's guidance, while most urgent for the first trimester, is not trimester-specific. While fetal neural tube vulnerability is greatest in weeks 1–12, heat stress in later pregnancy can trigger preterm labor, worsen dehydration, or stress the fetus. Pregnancy is a temporary condition; forgoing saunas for nine months is a small, safe sacrifice. Wait until after delivery.
Q: Are infrared saunas really "safer" than traditional saunas in pregnancy?
A: No. Despite operating at lower air temperatures (typically 40–65°C vs. 70–90°C), infrared saunas raise core body temperature comparably to traditional saunas because they deliver radiant heat directly to the body, bypassing air temperature as a limiting factor. Both carry the same fetal risk and should be avoided equally.
Q: What should I do if I crave the relaxation sauna provides during pregnancy?
A: The relaxation you seek from a sauna—stress relief, muscle infrared sauna for muscle recovery relaxation, a sense of wellness—can be achieved through safer modalities: gentle prenatal massage, warm (not hot) baths at body temperature, guided meditation, prenatal yoga, and walking in nature. These evidence-based practices support both relaxation and fetal health without thermal risk. Discuss options with your obstetrician or a prenatal wellness provider.
Related Wellness Resources
For more evidence-based information on sauna health and wellness, explore these articles on Peak Saunas' wellness blog:
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Infrared Sauna Benefits for Recovery and Athletic Performance
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How to Use an Infrared Sauna Safely: Best Practices and Contraindications
Disclaimer: This article is educational and does not constitute medical advice. All recommendations regarding sauna use during pregnancy should be made in consultation with your obstetrician or midwife. Peak Sau