Is it safe to have hot baths during pregnancy?

It's best to be cautious about having a hot bath, although having a warm bath is fine – and a great way to relax during pregnancy.

The water should be cool enough so that you can get straight in without having to get in bit by bit. It also shouldn't affect the colour of your skin and make it red, or make you sweat.

Test the water with your elbow or forearm before getting in. This part of your body is more sensitive to temperature than your feet or hands.

You need to be cautious because a hot bath could push up your core body temperature, and this could be dangerous for your baby. Studies on animals suggest that overheating, especially in the early months of pregnancy, may cause birth defects in their offspring.

Research on the effects of hot water on women during pregnancy is still ongoing. But we do know that overheating, especially in the first trimester, can cause birth defects that affect how your baby’s brain and spine develop. These are called neural tube defects (NTD). Spina bifida is one example of an NTD.

There’s some evidence that it may be safe for you to sit in a bath up to 40 degrees C for up to 20 minutes. This short exposure to heat may not be enough to raise your core temperature too high. But it can be difficult to measure the precise time and temperature, so it's best to be cautious, to be on the safe side.

If your bath water is too hot, you could also feel faint or sick, as the heat can lower your blood pressure a bit too much. This can affect blood flow to your baby, which is unsafe at any stage of your pregnancy.

Tempting though it is to relax in a scented bath, it's best not to use perfumed bubble bath, bath salts or bath oils during pregnancy. This is because they can alter the acidic balance of your vagina and make you more likely to develop thrush. Thrush can be very uncomfortable for you and, if left untreated, could pass to your baby during birth. If you miss the smell of perfumed bubbles, try lighting some scented candles instead.