Pregnancy: sport, sauna, hammam, hot bath… are we entitled to it or not?

Have a little sauna session, go for a few minutes to relax in the hammam, take a good hot bath, do an intense workout … By dint of bans during pregnancy, we no longer know very well what to do or not to do when you are pregnant. And it is clear that we often end up not doing much, for fear of damaging the health of the baby!

However, a number of alleged bans are in fact false beliefs, and many actions would be discouraged because of a precautionary principle taken to the extreme. And this would be particularly the case for sports sessions, going to the sauna / hammam or taking a bath.

Sauna, hammam, hot bath: a vast scientific study takes stock

Grouping together data from no less than 12 scientific studies, a scientific meta-analysis on these activities during pregnancy was published on March 1, 2018 in the “British Medical Journal of Sports Medicine“.

The researchers point out that the internal body temperature (at the level of vital organs) is said to be teratogenic, that is to say harmful to the fetus, when it exceeds 39 ° C. It is therefore accepted that a body temperature between 37,2 and 39 ° C does not in itself harm the fetus, and all the more so if the increase in temperature does not last very long.

For this vast study, scientists from the University of Sydney (Australia), therefore gathered the data and conclusions of 12 studies carried out on 347 pregnant women exposed to an increase in body temperature, due to physical exercise, d ” a sauna or hammam session, or even a hot bath.

Precise and reassuring results

The highest body temperature observed during these studies was 38,9 ° C, just below the threshold considered to be teratogenic. Immediately after the activity (sauna, steam room, bath or workout), the highest average body temperature of the participating pregnant women was 38,3 ° C, or again below the threshold of danger for the fetus.

Concretely, the study summarizes very precisely the conditions under which pregnant women can do these different activities that increase body temperature. According to the study, it is therefore possible for a pregnant woman to:

• exercise for up to 35 minutes, at 80-90% of your maximum heart ratee, at an ambient temperature of 25 ° C and a humidity of 45%;
• do a aquatic sports activity in water of 28,8 to 33,4 ° C for 45 minutes maximum;
• take a hot bath at 40 ° C, or relax in a sauna at 70 ° C and 15% humidity for a maximum of 20 minutes.

As these data are both very precise and not very concrete, and it is not always easy to engage in these activities with full knowledge of the temperature and humidity of the room, we preferred to ask the lighting of a gynecologist.

Sauna, hammam, sport & pregnancy: the opinion of Prof. Deruelle, member of the National College of French Obstetrician Gynecologists

For Prof. Philippe Deruelle, gynecologist and sObstetrics General Secretary of the CNGOF, this meta-analysis of twelve studies is rather reassuring for pregnant women: “ We are on fixed protocols, for example with a bath at 40 ° C, while in reality, the bath cools quickly, and the body is not totally immersed, so we are rarely in these extreme protocols “. However, even with such protocols, the limit of dangerousness for the fetus (or teratogenicity) is not reached, therefore “ there is room “, Estimates Professor Deruelle, for whom we can quite” rely on this meta-analysis to reassure women ».

Physical activity during pregnancy: safe and even recommended!

For Professor Deruelle, this analysis is all the more reassuring as it clearly shows that physical activity is largely safe “ For years, doctors have used this teratogenic effect of hyperthermia to tell pregnant women not to exercise, arguing that the rise in body temperature is harmful to the fetus. », Regrets the gynecologist. ” We can see today, through these studies, that this is not at all true, and that we can quite do physical activity during pregnancy, on the contrary! This physical activity simply has to be adapted. We are not going to do exactly what we used to do during pregnancy. The physiology of pregnant women requires adaptation, with a slightly reduced duration or intensity of sport, sauna or bath. », Explains Philippe Deruelle.

« Today, if all pregnant French women did ten minutes of sport a day in an appropriate way, I would be the happiest obstetrician “, He adds, pointing out that again, the study evokes a protocol of 35 minutes of physical activity, at 80-90% of its maximum heart rate, which is very physical, and rarely achieved. If there is no risk to the fetus under such conditions, it is therefore safe to do a short session of brisk walking, swimming or cycling during pregnancy.

Sauna and hammam during pregnancy: a risk of discomfort and feeling unwell

When it comes to going to the sauna or hammam when you are pregnant, Professor Deruelle is on the other hand more careful. Because even if, according to the meta-analysis, a sauna session at 70 ° C for 20 minutes does not increase the temperature beyond the limit harmful to the baby, this closed, saturated and very hot environment is not very pleasant when you are pregnant. “ The physiology of the pregnant woman makes her go tolerate high temperatures less well, as soon as beta-HCG appears, due to vascular changes and feeling tired », Explains Professor Deruelle. He points out that while it can be nice to go to the sauna when you’re not pregnant, pregnancy is a game-changer and may make the situation very uncomfortablee. Note that the sauna and hammam are also not recommended for people suffering from heavy legs and varicose veins, as this affects the blood circulation. As pregnancy often rhymes with heavy legs, it would be better to ease off on sauna and hammam sessions.

For the bath, on the other hand, no problem, since even water kept at 40 ° C for 20 minutes does not represent a danger for the baby in utero. ” I’m quite uncomfortable that some doctors contraindicate baths », Admits Professor Deruelle. ” This is not based on any scientific study, it is an outright paternalistic ban He adds. Do not deprive yourself of a good hot bath during pregnancy if you feel like it, especially as it can help you relax at the end of pregnancy as childbirth approaches.

Overall, and in view of this very reassuring meta-analysis of 12 studies, it is advisable not to deprive yourself of physical activity, a (small) hammam / sauna session or a good hot bath if you are wish it, by remaining attentive to the signals of his body and adapting his activities accordingly. To every woman of find your own limits during her pregnancy in terms of heat.