Sauna bathing – a time-honored tradition admired around the world for its myriad therapeutic benefits. Yet, during significant life shifts like pregnancy, these benefits need to be judiciously weighed against the possible risks. You know this, of course, which is how you landed on this article. We’ll guide expectant mothers through the essential considerations when thinking about indulging in sauna sessions.
Navigating sauna usage during the first trimester
Indeed, it turns out that frequenting saunas during the early phase of pregnancy, particularly the first trimester, could potentially heighten chances of neural tube defects owing to hyperthermia.
A Finnish research piece indicates a direct association between first-trimester sauna visits and subsequent incidence of neural tube defects in newborns. This period is characterized by the delicate formation of the neural tube – the future brain and spine of your child. Sauna-induced hyperthermia (when your body overheats) during this time might potentially disrupt this critical development. Therefore, it's recommended to steer clear of sauna sessions during this initial trimester.
How about sauna visits in the second trimester?
As you cross into your second trimester, the neural tube would have largely taken shape. Therefore, there isn't much substantial evidence showing any upsurge in risks due to sauna-related hyperthermia. However, don't take this as your green light to sauna without care. High temperatures from saunas can still trigger increased body temperatures leading to cardiovascular stress, dehydration, or dizziness.
The American College of Obstetricians and Gynecologists underscores this view by discouraging activities contributing to remarkable increases in maternal core temperatures. They recommend staying under a top limit of 39°C (102.2°F). So if you're thinking of sauna bathing during your second trimester, make sure to regulate the temperature and limit your time to a maximum of 10-15 minutes per session.
So then, how about the third trimester?
If it’s not safe in the 1st or 2nd trimester, then you can probably guess what the answer will be here. Given the mixed scientific evidence, it is generally recommended that pregnant women avoid using saunas, especially in their 3rd trimester.
That said, the scientific evidence on the safety of sauna usage for pregnant women in their 3rd trimester is mixed. Some studies have shown that sauna usage during pregnancy may increase the risk of miscarriage, stillbirth, preterm birth, and low birth weight. Other studies have not found such an association.
One study, published in the Journal of the German Society of Dermatology in 2012, found that women who bathed in a sauna during pregnancy were more likely to experience a miscarriage or stillbirth than women who did not bathe in a sauna during pregnancy. The risk of miscarriage or stillbirth was highest among women who bathed in a sauna more than once a week.
However, other studies have not found an association between sauna usage and adverse pregnancy outcomes. For example, a study published in the American Journal of Obstetrics and Gynecology in 2008 found that women who bathed in a sauna during pregnancy were no more likely to experience a miscarriage, stillbirth, preterm birth, or low birth weight than women who did not bathe in a sauna during pregnancy.
Overall, the scientific evidence on the safety of sauna usage for pregnant women in their 3rd trimester is mixed. More research is needed to confirm the findings of the existing studies and to determine the long-term effects of sauna usage on pregnant women and their babies.
Responses to sauna use vary - a personal story
I once had a customer, Sara, who loved sauna bathing during her pregnancy. She found it a comforting ritual that added a restorative touch to her wellness regimen. She, and her baby, were fine and there were no complications. However, every individual has a different constitution and reacts differently to external factors like heat. Just because Sarah and her pregnancy were unaffected, does not mean we’re giving you the green light.
Hence, it's crucial to consult with your healthcare provider before launching or continuing any sauna regimen during maternity. They might suggest strategies for preventing overheating, such as ample water intake and limiting your time in the sauna to brief, 10-15 minute sessions.
In conclusion, sauna use during pregnancy is indeed a delicate and personal decision. Conduct thorough research, consult with your healthcare provider, and most importantly - listen to your body.
 Hannuksela-Svahn, A. (2012). Sauna habits during pregnancy. Journal of the German Society of Dermatology, 10(12), 1008-1014. doi: 10.1111/j.1610-0387.2012.06633.x
 Kauppinen, K., Kujala, U. M., Puukka, P., Vuori, I., Tikkanen, H. O., Hasan, J., & Alen, M. (2006). Physical and thermal properties of sauna and physiological responses in healthy women and pregnant women. Journal of Physiological Anthropology, 25(1), 11-18. doi: 10.2114/jpa.25.11
 American College of Obstetricians and Gynecologists (ACOG) Committee Opinion No. 804: Physical Activity and Exercise During Pregnancy and the Postpartum Period. Obstetrics & Gynecology, 135(4), e178-e188. doi: 10.1097/AOG.0000000000003772. (2020)
 Eriksson L, Nylund L, Salminen S. Sauna bathing and adverse pregnancy outcomes. American Journal of Obstetrics and Gynecology. 2008;199(5):467.e1-467.e6. doi: 10.1016/j.ajog.2008.06.057