There's little research on using saunas, jacuzzis, hot tubs and steam rooms during pregnancy.
You may choose to avoid them because of the risks of overheating, dehydration and fainting.
You're likely to feel warmer than normal during pregnancy. This is caused by hormonal changes and an increase in blood supply to the skin.
These hormonal changes can also make pregnant women feel faint.
When you use a sauna, jacuzzi, hot tub or steam room, your body is unable to lose heat effectively by sweating. This means your body's core temperature rises.
It’s possible that a significant rise in your core temperature could be harmful in pregnancy, particularly in the first 12 weeks.
If you overheat, more blood flows close to your skin to help cool your body by sweating.
This means there's less blood flow to internal organs, such as your brain.
If you do not get enough blood and oxygen to your brain, it can make you feel faint.
You may want to avoid situations where you could get too hot, such as sitting in a jacuzzi or steam room.
Overheating
When you use a sauna, jacuzzi, hot tub or steam room, your body is unable to lose heat effectively by sweating. This means your body's core temperature rises.
It's possible that a significant rise in your core temperature could be harmful in pregnancy, particularly in the first 12 weeks.
Feeling faint
If you overheat, more blood flows close to your skin to help cool your body by sweating.
This means there's less blood flow to internal organs, such as your brain.
If you do not get enough blood and oxygen to your brain, it can make you feel faint.
You may want to avoid situations where you could get too hot, such as sitting in a jacuzzi or steam room.
Water temperature
If you're using a hydrotherapy pool, the temperature should not be above 35C.
Some hot tubs can be as hot as 40C, so it's best to avoid them.
Find out more about exercising during pregnancy
Get more answers to questions about pregnancy