Causes of miscarriage

Miscarriage is by far the biggest cause of pregnancy loss in the UK, and it’s also the least understood.

We still don’t know why all miscarriages occur.  That’s why Tommy’s  has opened the UK’s only research centre dedicated to understanding  miscarriage and preventing it.

1 in 4 women suffer a miscarriage at some time in their lives, and a small proportion of couples suffer multiple losses. Only 1 in 100 women suffer three miscarriages in a row (recurrent miscarriage) and most couples who experience a loss go on to have a successful pregnancy in the future.

Find out more about recurrent miscarriage and what can cause it here

It’s important to know that the vast majority of miscarriages aren’t caused by anything that you or your partner have, or haven’t done.

If a miscarriage occurs  during the first trimester (the first 12 weeks of pregnancy), it’s usually caused by problems with the unborn baby.  About   85% of miscarriages occur during this period, and are known as “early” miscarriages.

Find out more about early miscarriage and what can cause it here

During the second trimester (between weeks 13 and 24, a “late” miscarriage may happen as a result of an underlying health condition.

Find out more about late miscarriage and what can cause it here

Factors that increase the risk

  • Getting older. A woman of 30 has a 20 per cent chance of miscarriage, but a a woman of  42 has  a 50 per cent chance of losing the baby.  This is because, as you age, the quality of your eggs diminishes.
  • Underlying health problems, such as poorly controlled diabetes.
  • Lifestyle factors such as too much caffeine , heavy drinking, smoking and  using recreational drugs.
  • Obesity.

Lifestyle changes you can make

There is clear evidence that your lifestyle can affect your chance of having a baby, so there are several things you can do to limit the risk of miscarriage and increase the chances of a healthy pregnancy. 

You should  consider:

All of these things we know will increase your chances of a healthy pregnancy.

Common misconceptions

Many women and couples who have had, or are experiencing a miscarriage, worry that they may somehow have caused it to happen.  There are many common concerns which simply aren’t linked to miscarriage at all.

  • Your emotional state, such as stress or depression
  • Having a shock or fright
  • Exercise (but do consult your GP or midwife about how much exercise is suitable)
  • Lifting or straining
  • Working, even if it involves sitting or standing for long periods
  • Having sex
  • Travelling by air
  • Eating spicy food

None of these factors have any known link to miscarriage.

Tommy's carries out vital research into miscarriage – find out more about our miscarriage research. 

Read more about miscarriage

  • Chemical pregnancy

    A chemical pregnancy is the term given to a pregnancy which ends in miscarriage before the fifth week of gestation.

  • Health professional comforting woman.

    Missed miscarriage

    This type of miscarriage can be really shocking for a mother.

  • Partner comforting woman.

    Incomplete miscarriage

    If you start to miscarrying naturally, and experience some bleeding, this indicates that the pregnancy is over and the process of losing your baby is underway.


  1. Sources: NHS Choices Miscarriage – Causes Page Review: 21/05/15, Next Review: 21/05/17


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Last reviewed on August 1st, 2016. Next review date August 1st, 2019.

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  • By Midwife @Tommys on 12 Aug 2016 - 10:43

    We are so very sorry to hear that you are currently experiencing a miscarriage, I hope that you have support from the hospital and people around you. If you would like to talk please do call us on 0800 0147 800 or email Please look after yourself

  • By Anonymous (not verified) on 12 Aug 2016 - 09:57

    My pregnacy was 8weeks and i just hade a miscarriage.and bleeding badly

  • By Deirdre@Tommy's on 19 Jul 2016 - 10:07

    We are very sorry for your and your daughter’s loss. Internal examinations are not normally carried out in early pregnancy unless there is a specific reason for it. Whatever the reason was, an internal examination does not cause miscarriage or pregnancy loss. Without knowing more about your daughter’s pregnancy history we can’t give any more information. If you (or she) would like to call us on 0800 0147 800 or email on we can talk it through with you. Sorry again for your loss.

  • By Anonymous (not verified) on 13 Jul 2016 - 12:42

    My daughter was 9 weeks pregnant and miscarried, this one day after an internal examination which expectant mothers I am told have to go through. Could this internal examination have been the direct cause of her miscarrying her baby?

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