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


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


Hide details

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

Was this information useful?

Yes No


  • By Anonymous (not verified) on 10 Jul 2018 - 19:11

    I've had 2 ectopics and had my left tube removed since then I've had a miscarriage at 13 weeks and now another at 6 weeks. Nothing present during the early scan and HCG level is 166 so nurse said it's an early miscarriage. I've had a blood test to check for Thrombophillia, but awaiting the results. Keep being told that NHS won't do anything until I've had 3 miscarriages, I am going to go private as I can't take the pain and loss anymore but is there something specific I should be checking for as to why I keep having these loses such as clots or cervical checks?

  • By Midwife @Tommys on 12 Jul 2018 - 14:08

    I am so sorry to hear what you have been through and continue to go through. The general guidance is that the NHS do not normally offer tests and investigations until three consecutive miscarriages, which is what you have been told, and it is understandably extremely frustrating and upsetting. Sometimes some basic test are offered but this is down to the discretion of the health professional and they are not under any obligation to do so.
    With regards to cervical checks, it would be unlikely that it was your cervix that is the problem as all your losses have been in the first trimester, cervix problems are often a cause of second trimester losses not first. You are already having a blood test for thrombophillia, so when you get the results of this this may give you some more information about if you need to take aspirin and/or heparin in next pregnancy.
    It is completely your choice if you would like to access private care in the meantime, if this is an option for you. They will discuss what tests they can offer you and what their plan would be based on your history so far.
    I wish you all the best, please do be in touch with us if we can support you further.
    Best wishes
    Tommy's midwives

  • By Anon (not verified) on 8 May 2018 - 17:31

    I had a miscarriage at 11 weeks. I had a scan at 10 weeks strong heart beat and perfect little fetus developing. I got a temperature and couldn’t reduce it by the 4 day I had pain and cramping told not to worry by early pregnancy unit and then at 13 week booking had a scan to check and all had gone. I believe the temperature a virus cause the miscarriage but when I speak about this now people think I’m wrong. That it must be genetic. Why do health professionals not listen to patients after miscarriage - maybe if we did we would understand much more about the causes and risks.

  • By Midwife @Tommys on 10 May 2018 - 14:36

    Hi there
    I am so sorry that you lost your baby and you feel as if nobody has listened to you. Unfortunately, there can be many reasons for miscarriage, so it really is difficult to know if your virus/temperature may or may not have contributed in some way to the loss. It is possible that it wouldn't have helped, but i feel that it is foolish of your team caring for you to dismiss it entirely. However, whatever the reason for it, it is not possible to determine it for sure. It sounds as if you are really struggling emotionally with the loss, which is totally understandable. If you feel you need some advice and information about how to access counselling, we can assist you with this. You can get in touch via email [email protected] or 0800 0147800
    I really hope that you are doing ok and get in touch if you need us
    All the best
    Sophie Tommy's Midwife

  • By Anonymous (not verified) on 6 Aug 2017 - 08:26

    I saw,the baby and HB at 8.5 weeks and all looked OK. At 12 weeks there was no HB and baby measured 8.2, days. The midwife said the baby likely passed after the internal scan. Could the scan be the reason I miscarried. When she was checking stuff it did hurt me

  • By Midwife @Tommys on 7 Aug 2017 - 11:51

    I am so sorry about your miscarriage and hope that you have good support to help you. There is no evidence to suggest that a vaginal scan can harm the growing baby. It is more likely that the timing was by chance. Best wishes to you x

  • 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 [email protected] 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 [email protected]'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 [email protected] 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?

Add new comment