SaunaScape

Photo by Schwangerschaft on Flickr

The short answer is yes, in moderation.

A Canadian team published “Suggested limits to the use of the hot tub and sauna by pregnant women” in the Canadian Medical Association Journal in 1981.

Other research had established that a body temperature of 38.9°C (102°F) can be teratogenic, meaning it can cause birth or developmental defects in an unborn baby. To test this, they recruited 20 women who were of child-bearing age, but not pregnant and measured the time it took for their internal temperatures to rise to this temperature.

Average core temperatures of women of childbearing age who could stay in a bath for the given time.

In hot tubs they found it took:

• 15 minutes in a 39°C (102°F) hot tub,
• 10 minutes in a 41°C (106°F) hot tub,

They then had their volunteers spend time in an 81°C (180°F) sauna. Most women left after 13 minutes, all had left by 25 minutes due to discomfort. None had their core rise to damaging temperature.

They cite a separate study where 60 men and women bathed in a sauna for as long as possible. Of these, 20% were able to remain in the sauna long enough for their core to rise above 39°C (102°F), but data on whether these were men or women was not published with the data.

So you can take hot baths or saunas while pregnant. You just need to be careful to limit your time in them, and be sure to cool down gently and fully before taking another session. Women in Finland regularly bathe in saunas throughout their pregnancy, but limit their time in the sauna to 6-12 minutes, and they stay away from hot saunas.

“But what happens if I stay in a sauna too long?” you may ask. They researched this as well:

“Among 28 dysmorphic infants exposed to hyperthermia between 4 and 14 weeks’ gestation all the survivors had mental deficiency and most had altered muscle tone, including hypotonia, with increased deep-tendon reflexes. More of those exposed to hyperthermia at 4 to 7 weeks had facial defects. In 3 of the 28 pregnancies the hyperthermia was due to a long stay in a hot tub or sauna. In one instance the pregnant woman had remained in a tub that was reported to have a water temperature of 106°F (41.1 °C) for nearly an hour”

So, the consequences can be severe if you’re not paying attention.

[Suggested limits to the use of the hot tub and sauna by pregnant women]

Photo posted by Dru! on Flickr

Our news ticker has been lit up recently with the news of the recent settlement of a lawsuit where an Indiana man passed away after collapsing in the sauna of his YMCA. We feel deep sympathy for the man’s friends and relatives, as losing a loved one suddenly is always difficult, especially when you’re not dealing with individuals, but through the American legal / insurance system, as was the case for this man’s poor wife. But that’s a topic for another blog.

This brings the topic to light that heat bathing can be dangerous. According to Wikipedia, raising your core body temperature just 6°F / 2°C can be life threatening. Any additional temperature rise can begin to cause brain damage. For pregnant women, the dangers to their unborn child begin sooner, with a core temperature rise to 102.0°F /38.9°C. Normal body temperature is 98.6°F / 37.0°C.

In 1991, The American Journal of Public Health published a review of “The Health Hazards of Saunas and Spas and How to Minimize Them.” Most of this article is a review of the literature published to date, much of it in the 1998 Annals of Clinical Research special edition on saunas. (We have not been able to find this publication. If you have a copy, we would be grateful if you would share this with us.)

In the study, the author recommends:

Persons with heart disease, hypertension, seizure disorders, diabetes, or significant obesity; persons who have ingested alcohol, narcotic drugs, or medications that can result in drowsiness or interfere with the body’s temperature-regulating mechanism; or persons who are over 65 years of age must limit their stays in saunas or spas to 5 or at the most 10 minutes at a time. Similar precautions should be observed by women in the first trimester of pregnancy.

Even healthy adults would be well advised not to stay in for more than 10 to 15 minutes at a time.

Fainting is the greatest hazard for heat bathers. In a test of 60 otherwise healthy adults, 5% of them fainted after a 20-minute sauna session. The test was repeated with 61 children under 12, and 3% of them fainted after a 10-minute sauna session. The author notes that if you have heart disease, or have used alcohol or drugs your risk of fainting increases.

Falling from fainting while in or exiting the bath can cause injuries by itself, or compounded by the hot stove components. Fainting with loss of consciousness, especially in an unsupervised area,  can cause more severe problems if you are not promptly removed from the heat or water.

Heart arrhythmia can  be caused by sauna bathing. This is especially true if you have heart disease, or arteriosclerosis. What many people don’t realize is that alcohol, cocaine and other drugs that affect the heart, temperature regulating mechanisms, or cause drowsiness, can also increase your risk for cardiac arrhythmia. This carries over into the hangover phase as well.

Sweating out a hangover in a sauna is a bad idea.  Evidence presented in the paper shows that if you are hung over, you are more likely to experience cardiac arrhythmia in the sauna. Even the wild children at Partiers.com admit it is as bad as “Hair of the Dog.”

As part of this study, the author polled US medical examiners about heat bathing related deaths from 1983-1988. Of the 7 sauna-related deaths in that period, 6 were in people who had used alcohol or had heart disease. All were over 12 years old, and 5 of the 7 were over 65 years old.

In that same time period, 47 spa / hot tub deaths were reported.  45% of the fatalities had used either alchohol and/or cocaine. Another 17% of these were people with heart disease.

Other hazards found in the study were:

• Diabetics taking insulin via injection can absorb it more quickly due to dilation of the blood vessels near the body surface.
• Men whose partners are trying to conceive should avoid the sauna: A single 20-minute exposure to a sauna at 176°F / 80°C can decrease sperm count for up to 5 weeks!
• Women who are or may be pregnant should be careful around the sauna: A small temperature rise in your body can damage your unborn baby, especially in the first trimester. In the last trimester, elevated body temperatures can induce labor.

I did a quick study of sauna-related injuries from 2006 and 2007, reported by hospitals to the US Consumer Products Safety Commission. There were a total of 23 injuries in those two years. All injuries were minor enough to allow the patients to be released without admission to the hospital. Most were burns, falls or fainting episodes.  However, their data does not tell the whole story, as a family in Indiana will tell you.