In a nutshell

Yes, it's safe to use a hot water bottle or a microwaveable heat pad during pregnancy, although it's sensible not to place either directly on your bump. Hot-water bottles and heat pads are actually a great way of easing pains and cramps in pregnancy – and the early stages of labour.

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But won't a hot water bottle get my baby overheated?

Many pregnant women do worry that the heat from a hot water bottle or heat pad could be bad for their baby. That's because they might have heard that if you're pregnant and your core body temperature rises above 39°C (102°F) for long periods of time, it can be harmful for your developing baby, particularly in the 1st 12 weeks of pregnancy¹.

But a hot water bottle or heat pad – sited away from your bump – won't bring up your whole core body temperature in this way. So, while pregnant women are often advised not to use steam rooms, saunas and Jacuzzis², using a heat pad or hot water bottle doesn't carry anything like the same risk.

How can a hot water bottle or heat pad can be helpful in pregnancy?

Pregnancy can bring with it some new aches and pains as increased amounts of the hormones relaxin and progesterone relax your ligaments and joints (in preparation for labour) and also when your growing bump and swelling breasts make your centre of gravity shift. The warmth of a hot water bottle or heat pad can be very effective at soothing and relieving an achy lower back or painful hips or upper thighs.

A warm hot water bottle or heat pad can also be relaxing in the early stages of labour – and useful at relieving any pain.

More like this

As I've mentioned earlier, it is always sensible to avoid holding the hot water bottle or heat pad directly on your bump. And you should always follow the advice in How to use a hot water bottle safely, below, which applies whether you're pregnant or not.

If you are experiencing pain or discomfort that is not improving or have any other concerns, please seek medical advice.

How to use a hot water bottle safely

  • Avoid placing it directly on your bump
  • Do not place it directly on any other part of your skin unless it has a cover on or you put a towel in between your skin and the hot water bottle
  • Check your hot water bottle has a safety standard mark on it. The current standard is British Standard BS 1970
  • Check your hot water bottle for any signs of splits, perishing rubber or signs of wear and tear. Replace it if you see any of these
  • Don't fill your hottie with boiling water. Let the boiled water cool for a few minutes before pouring it into the hot water bottle
  • Don't overfill it: fill it to a maximum of about two-thirds
  • Make sure you close the top firmly before using it

How to use a heat pad safely

  • Avoid placing it directly on your bump
  • Read the instructions carefully
  • Start with the lowest setting and only increase the heat slowly
  • Do not use for more than 20 minutes at a time
  • Do not use overnight

References:

1 .Ambient temperature during pregnancy and fetal growth in Eastern Massachusetts, USA. Leung et al. International Journal of Epidemiology. Vol 52; issue 3. June 2023, pages 749–760.
2. Is it safe to use a sauna or jacuzzi if I'm pregnant? NHS Online

Pic: Getty

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Authors

Dr Philippa Kaye works as a GP in both NHS and private practice. She attended Downing College, Cambridge, then took medical studies at Guy’s, King’s and St Thomas’s medical schools in London, training in paediatrics, gynaecology, care of the elderly, acute medicine, psychiatry and general practice.

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