Hot tubs and saunas can be a pleasurable way to relax and soothe aching muscles, but a leisurely soak in a bathtub is a better option when you’re expecting.
Unlike the hot water found in a bath, which cools down as you sit in it, the water in hot tubs is expressly designed to stay hot and it’s usually a lot hotter than bath water. The preferred temperature for bath water is two degrees higher than the average body temperature or approximately 100.˚ Hot tubs are generally programmed to reach 104,˚ a temperature that is attained within 10 to 20 minutes.
The consistently high temperatures found in hot tubs and saunas can raise a woman’s core body temperature and that in turn may negatively affect the development of her unborn child. A core body temperature of 101˚ or more, whether it is caused by a fever or soaking in a hot tub, is cause for concern because some studies have suggested a link between elevated maternal body temperature and birth defects.
A 2011 study by the National Institutes of Health suggests that babies born to women who experience elevated temperatures during the first weeks of pregnancy are at a higher risk for the kind of birth defects that affect a baby’s brain and spinal cord. Other studies suggest a link between time spent in hot tubs and saunas with other birth defects and also miscarriages, although more research is needed.
Another problem with frequenting hot tubs and saunas while pregnant is the possibility of becoming dehydrated and feeling faint. Hormonal changes during pregnancy already boost a woman’s body temperature, making it slightly warmer than the average of 98.6.˚ Women who don’t remember to drink enough water during pregnancy may be prone to dehydration and have a greater likelihood of fainting when exposed to higher temperatures.
Experts suggest avoiding hot tubs and saunas completely during the first trimester of pregnancy. If you do feel the urge to indulge during your second and third trimester, it’s important to observe these rules:
- Don’t stay in the sauna or hot tub longer than ten minutes.
- Avoid the source of the hot water in hot tubs, as the temperature is higher there.
- Get out if you feel uncomfortable.
- Don’t use a hot tub or sauna if you already don’t feel well, especially if you might have an elevated temperature due to a fever.
- Don’t visit the hot tub or the sauna after an exercise session, as exercise can also raise your body temperature.
Be sure to discuss exercise during pregnancy, as well as any hot tub and sauna use, with your healthcare provider.