When you're pregnant, nearly every wellness decision comes under scrutiny—and for good reason. Your body is doing extraordinary work, and the choices you make ripple into your baby's development. One question we hear frequently at Peak Saunas is: Can I safely use a sauna or hot tub while pregnant?
The short answer: the American College of Obstetricians and Gynecologists (ACOG) recommends caution, especially during the first trimester. But understanding why this guidance exists—and what it means for infrared sauna use specifically—requires a deeper dive into the science of maternal overheating, fetal development, and heat stress.
This article breaks down ACOG's official pregnancy sauna recommendations, explains the physiological risks of maternal hyperthermia, and explores what the research tells us about infrared heat exposure during pregnancy.
ACOG's Official Stance: Maternal Hyperthermia & First-Trimester Risk
The ACOG Committee Opinion on exercise during pregnancy emphasizes that maternal core temperature elevation—particularly in the first trimester—poses a theoretical risk to fetal development. While the exact threshold for harmful hyperthermia in humans remains debated, animal studies and observational data have long suggested that elevated core temperatures during organogenesis (roughly weeks 4–8) may increase the risk of neural tube defects and other structural anomalies.
ACOG's guidance specifically advises pregnant people to:
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Avoid activities that raise core body temperature to >38.9°C (102°F) during pregnancy, particularly the first trimester
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Limit time in hot tubs to 10 minutes or less if they choose to use them
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Be cautious with saunas, especially traditional high-heat models, as they can elevate core temperature rapidly
The rationale is straightforward: unlike exercise, where muscular exertion and cardiovascular infrared sauna cardiovascular health guide adaptation provide some thermoregulatory compensation, passive heat exposure (such as sauna or hot-tub use) offers fewer physiological safety valves. A pregnant person's body is already managing a higher baseline metabolic rate and fluid shifts; adding uncontrolled external heat can push core temperature into a range where risk becomes non-trivial.
Why Infrared Saunas Present a Different Risk Profile
Not all saunas are created equal when it comes to pregnancy safety.
Traditional Finnish dry saunas operate at 70–100°C (158–212°F) and raise core body temperature through convective and radiative heat transfer. A typical 15–20 minute session in a traditional sauna can elevate core temperature by 1–2°C, depending on humidity, duration, and individual physiology.
Infrared saunas operate at lower ambient temperatures (typically 40–60°C / 104–140°F) but use far-infrared radiation to penetrate skin and underlying tissues, theoretically delivering heat more directly to the body's interior. Research comparing the two shows important differences in thermal response.
In a 2022 study of 10 healthy women, infrared sauna produced a mean tympanic (core) temperature rise of +1.05°C, which was significantly greater than control conditions or exercise of equivalent duration—a finding that underscores infrared saunas' potent thermal effect despite their cooler ambient setting. While this study was conducted in non-pregnant, healthy women and represents a single acute exposure, it illustrates why infrared saunas cannot be assumed "safer" simply because the cabinet is cooler.
The key point for pregnant users: Infrared saunas may elevate core temperature just as much as or more than traditional saunas in a shorter time frame. The lower air temperature does not equate to a lower thermal burden on the developing fetus.
The Fetal Thermoregulation Challenge: Why the First Trimester Matters Most
Understanding why ACOG singles out the first trimester requires a brief look at fetal physiology.
During organogenesis (approximately weeks 3–8 of gestation), the embryo is undergoing rapid cell division and tissue differentiation. The neural tube—precursor to the brain and spinal cord—is forming, and any significant disruption to normal gene expression during this window can have permanent consequences.
In animal models, maternal hyperthermia has been associated with neural tube defects, palatal clefts, and other congenital anomalies, with risk appearing dose- and timing-dependent. The human data are less direct—we cannot ethically conduct controlled hyperthermia studies in pregnant people—but observational evidence from maternal febrile illness and case reports of accidental hyperthermia exposure during pregnancy align with the animal findings, suggesting that a similar risk may apply.
Why not the second and third trimesters? By mid-pregnancy, organogenesis is largely complete, and the fetus has some capacity for thermoregulation via the umbilical blood flow. Maternal hyperthermia becomes less likely to cause structural defects, though it may still increase risk of preterm labor or intrauterine growth restriction in late pregnancy if severe or prolonged. This is why ACOG's most stringent warnings center on the first trimester.
What Does Research Say About Sauna Use & Pregnancy Outcomes?
Here's where we must be honest: the direct evidence on sauna use during pregnancy is sparse and observational.
No major randomized controlled trials have examined infrared or traditional sauna bathing in pregnant populations—for obvious ethical reasons. What we do have are:
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Observational studies linking maternal fever to adverse outcomes. Maternal infections causing fever, especially in the first trimester, are associated with increased risk of neural tube defects and autism spectrum disorders. By analogy, sauna-induced hyperthermia—which mimics some aspects of fever—may carry similar risk, though the temporal pattern and intensity differ.
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Animal and mechanistic data. Rodent and avian models consistently show that maternal hyperthermia during early development increases malformation rates, particularly neural tube defects, palatal clefts, and cardiac anomalies.
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Clinical experience and expert consensus. ACOG, the American Academy of Pediatrics, and other major obstetric organizations have coalesced around the recommendation to avoid maternal hyperthermia in pregnancy, particularly in the first trimester, as a precautionary measure.
The absence of a large cohort study showing "sauna use in pregnancy is safe" does not mean it is safe—it means the risk is uncertain and difficult to quantify in humans. Given that a safer alternative (avoidance) exists, the ACOG position is conservative but justified.
A Practical Framework: When, If Ever, Sauna Use Might Be Considered During Pregnancy
While Peak Saunas' core message aligns with ACOG guidelines—saunas are best avoided during pregnancy, especially the first trimester—we recognize that some pregnant people may have used saunas before learning of their pregnancy or may live in cultures where regular sauna use is deeply ingrained.
If a pregnant person and her obstetrician decide to revisit sauna use after the first trimester, a risk-mitigation approach might include:
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Keeping sessions very short: 5–10 minutes, rather than 20–30 minutes
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Avoiding both high-temperature traditional saunas and long-duration infrared sauna exposure: Aim for ambient temperatures no higher than 40°C (104°F) for infrared, or 50°C (122°F) for traditional
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Monitoring subjective thermal comfort: If she feels uncomfortably hot, overheated, or dizzy, exit immediately
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Staying well-hydrated before, during, and after
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Avoiding sauna use if experiencing symptoms of dehydration, preterm labor, or placental complications
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Discussing the specific plan with her obstetrician beforehand
Even with these precautions, the risk-benefit calculus tilts toward avoidance. There is no documented health benefit of sauna use during pregnancy that would outweigh the theoretical (and in early pregnancy, material) risk of fetal hyperthermia.
Beyond Pregnancy: Why Understanding Infrared Sauna Thermodynamics Matters
For non-pregnant users, the infrared sauna research base is broader and, in many areas, encouraging. Studies have documented potential benefits for cardiovascular function, recovery, mood, and pain management—though most evidence comes from traditional Finnish saunas, and infrared-specific research remains limited.
For instance, regular sauna use (4–7 sessions per week) in epidemiological cohorts has been associated with reduced cardiovascular and all-cause mortality (Laukkanen et al., 2015), though these studies enrolled primarily older Finnish men using traditional dry saunas, not infrared. Some smaller infrared sauna trials have shown improvements in endothelial function and heart-failure symptoms, though effect sizes vary and study quality is often modest.
The broader point: infrared saunas are not inherently "safer" or "gentler" than traditional saunas simply because they operate at lower air temperatures. Their deep-tissue penetration and rapid core-temperature elevation mean they must be respected as potent thermal exposures, particularly for vulnerable populations—including pregnant people, individuals with uncontrolled hypertension, severe heart disease, or acute illness.
FAQ: Pregnancy, Sauna, and ACOG Guidelines
Q1: I used a sauna or hot tub before I knew I was pregnant (in my first trimester). Should I be concerned?
A: A single brief sauna exposure is unlikely to cause harm. The main concern is repeated or prolonged hyperthermia during the critical window of organogenesis (weeks 3–8). If you had one session and did not experience symptoms of severe overheating (dizziness, fainting, extreme fatigue), the risk is low. That said, discuss it with your obstetrician, especially if you used a high-temperature sauna or stayed in for an extended period. Going forward, it is best to avoid saunas during the first trimester.
Q2: Are infrared saunas safer than traditional saunas during pregnancy?
A: Not necessarily. While infrared saunas operate at lower air temperatures, they can elevate core body temperature just as rapidly as or more rapidly than traditional saunas. ACOG's concern is maternal hyperthermia itself, not the mechanism of heat delivery. Both sauna types carry a theoretical risk during pregnancy, with infrared saunas offering no inherent safety advantage. If you are pregnant, both should be avoided, especially in the first trimester.
Q3: Is a 10-minute hot tub soak safe during pregnancy?
A: ACOG suggests that if a pregnant person chooses to use a hot tub after careful discussion with her obstetrician, limiting exposure to 10 minutes is a reasonable harm-reduction approach. However, the safest choice remains complete avoidance, particularly in the first trimester. If you do use a hot tub, keep it brief, monitor your core temperature (exit if you feel uncomfortably hot), and stay hydrated. Many hot tubs are maintained at 38–40°C (100–104°F), which is within the "caution zone" ACOG identifies. Verify the temperature and consider how your body responds.
Q4: Are there any sauna-derived health benefits that would justify use during pregnancy?
A: While regular sauna use is associated with cardiovascular and longevity benefits in non-pregnant populations, no such benefits have been documented specifically during pregnancy. Moreover, any potential benefit would need to be weighed against the established risk of fetal hyperthermia during organogenesis. In short: the cost-benefit calculation does not favor sauna use during pregnancy. Other evidence-based wellness practices—prenatal yoga, walking, water-based exercise, stress management—offer proven benefits without the hyperthermia risk.
Q5: Can I return to sauna use after pregnancy (postpartum)?
A: Yes. Once pregnancy is over and you are no longer breastfeeding (if applicable), sauna use can be safely resumed according to your personal preference and baseline health status. Some postpartum people find sauna use beneficial for stress relief, muscle infrared sauna for muscle recovery recovery, and mood—all well-supported by research in non-pregnant populations. However, if you are breastfeeding and concerned about sauna use affecting milk supply or composition, discuss this with your lactation consultant or obstetrician; the evidence suggests sauna use does not significantly impact breastfeeding, though individual variation exists.
The Bottom Line: ACOG Guidance and Infrared Sauna Safety in Pregnancy
The American College of Obstetricians and Gynecologists' recommendation to avoid maternal hyperthermia—particularly during the first trimester—is grounded in decades of animal research, observational clinical data, and physiological understanding of fetal development. Sauna use, whether traditional or infrared, is best avoided during pregnancy.
Infrared saunas, despite their cooler air temperature, are not exempt from this guidance. Research shows they elevate core body temperature robustly and can do so rapidly. For pregnant users, this thermal potency is a liability, not an advantage.
At Peak Saunas, we are committed to evidence-based wellness. That means acknowledging what we know with confidence—the safety of regular sauna use for non-pregnant, healthy adults—and what we must approach cautiously: sauna use during pregnancy. In this case, caution aligns perfectly with expert consensus.
If you are pregnant and considering sauna use, consult your obstetrician first. If you are planning pregnancy or are in the first trimester, the safest choice is to postpone sauna bathing until the second trimester at the earliest—and ideally until after pregnancy concludes.
For everything else, we're here to support your sauna wellness journey.
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NOTES ON THIS ARTICLE:
- Keyword integration: "ACOG pregnancy hot tub sauna avoid overheating official" is woven naturally throughout the headline