Sitting in a sauna or hot tub might seem like the perfect antidote for pregnancy aches and pains, but the medical truth is that pregnant women should stay out of saunas and hot tubs. The high temperatures in those environments can raise core body temperature, which could be dangerous for expectant mothers and, especially, their growing babies.
During pregnancy, a woman’s body is already working overtime, and if a pregnant woman’s temperature exceeds 102 degrees Fahrenheit, it can complicate the pregnancy and threaten the developing fetus. This is particularly true during the first trimester, but the American College of Obstetricians and Gynecologists recommends that pregnant women avoid saunas and hot tubs during all three trimesters.
Some saunas and hot tubs can be programmed to lower the temperature settings; nevertheless, just to be on the safe side, pregnant women should seek out alternative methods of relaxation, such as yoga, massage, and warm baths at home.
In a sauna, it’s hot all around, which can raise core temperature. For a pregnant woman, that condition (hyperthermia) could present a developmental risk for the baby growing inside her, especially during the first trimester.
One of the attractions of sitting in a sauna is the sense of releasing toxins and impurities through sweating because the surrounding heat causes blood vessels and pores to relax and open up. For a pregnant woman, however, that heavy sweating can result in dehydration and hypotension (low blood pressure). Hypotension can inhibit the flow of blood to the baby. It can also result in dizziness, which could be dangerous, either through loss of blood supply to the baby or if the woman falls.
Like a sauna, the chief risk of spending time in a hot tub is hyperthermia. Many hot tubs are programmed to maintain a water temperature of about 104 degrees Fahrenheit, which can raise a pregnant woman’s core temperature and keep it high, since people often sit almost fully submerged in the water. Just 10-20 minutes in a hot tub can raise body temperature to 102 degrees. Additionally, because the body is immersed in hot water, very little heat is released through sweating.
Hot tub use during pregnancy has been linked to having babies with brain and spinal cord-related birth defects, also known as neural tube defects (NTDs). A 1992 study published in the Journal of the American Medical Association states that “[e]xposure to heat in the form of hot tub [and] sauna…in the first trimester of pregnancy was associated with an increased chance for NTDs. Hot tub exposure appeared to have the strongest effect of any single heat exposure.” Some studies have also found a connection between hot tub use and increased risk of miscarriage, but these findings aren’t thoroughly conclusive.
Pregnant or not, there’s often nothing as appealing as the thought of coming home to a long, hot soak in a bubble bath. It’s okay for pregnant women to indulge, as long as the water is no warmer than 100 degrees Fahrenheit. Check the temperature before you get in to make sure it’s not too hot. Don’t stay in the tub for more than 15 minutes, and if you feel lightheaded or overheated, get out right away.
When you’re in the bath at home, you’re usually not fully immersed, so much of the upper body is exposed to the room’s air temperature, which will cool you off a bit. Another advantage to soaking in a bath at home instead of a hot tub is that the water starts to cool in a short while, which lessens the risk of overheating.