Do saunas and hot baths cause heat stress in pregnant women?
During pregnancy, women try to take care of themselves and avoid strenuous tasks, especially in warm weather. However, researchers have now found that even in warm weather, pregnant women can do sports, go to the sauna and use hot baths without endangering their unborn child's health.
In their study, scientists from the University of Exeter and the University of Sydney found that pregnant women can use saunas and perform hot baths without harming the health of the unborn child. The doctors published the results of their study in the English-language journal "British Journal of Sports Medicine".
Data from twelve studies were analyzed
The current study analyzed the results of a total of twelve studies carried out by July 2017. These reported on the core temperature response of 347 pregnant women and so-called heat stress, be it through physical exertion or through passive warming, e.g. B. by a sauna or sitting in a hot bath.
What do counselors say on this topic?
Current advice suggests that pregnant women should avoid heat stress based on concerns about possible risks of exceeding 39 ° C during pregnancy. However, the current study found that no woman exceeded the recommended core temperature limit of 39 ° C.
What did the measurements show?
The highest overall measured core temperature reached 38.9 ° C, 38.3 ° C for exercises on land, 37.5 ° C for exercises in water, 36.9 ° C for hot water and 37.6 ° C for sauna visits the scientists. Based on these results, the researchers say that pregnant women can safely do up to 35 minutes of intensive aerobic exercise (at 80 to 90 percent of their maximum heart rate) at air temperatures of up to 25 ° C and 45 percent relative humidity.
Guidelines for heat stress limits are not clearly defined
The experts also report that pregnant women can safely take part in aqua aerobic exercises for up to 45 minutes at water temperatures of 28.8 ° C to 33.4 ° C and can spend up to 20 minutes in hot baths (40 ° C) without reaching the recommended core temperature limit of 39 ° C - regardless of the stage of pregnancy. The researchers argue that current guidelines do not clearly define heat stress limits and can therefore discourage pregnant women from engaging in physical activity, although this could benefit both mother and child.
Is heat regulation increased during pregnancy?
The studies analyzed by the scientists included women at every stage of pregnancy. Some women showed a decrease in the increase in core temperature during pregnancy, which supports the theory that thermoregulation is increased during pregnancy. Although the underlying mechanism is unclear, the researchers suspect that changes in body mass and surface may play a role.
More research is needed
The experts noted some limitations in their review, such as: the small size of the study. They stress that more research is needed to determine safe exposure and environmental limits for pregnant women who are physically active in hotter climates. But their results suggest that the risk of heat stress is low.
The risk of heat stress from pregnant women is low
Health guidelines for pregnant women consistently state that bathing in hot water or staying in the sauna should be limited due to the increased risk of maternal hyperthermia and the consequent possible effects on fetal development. However, the current results indicate that the risk of heat stress is low, explains study author Dr. Ollie Jay of the University of Sydney. (as)