Why do miscarriages happen?
How common is miscarriage?
Recurrent miscarriages, is it just bad luck?
What contributes to miscarriage?
How can I help prevent miscarriage next time?
When can we start trying for a baby again?
My partner has miscarried, how can I help her?

Why do miscarriages happen?

When you conceive and a baby is created, it takes half its genes from the sperm and half from the egg that ovulated that month. At the exact time of conception, the cross-over of these genes takes place. Sometimes, for no reason other than bad luck, some information is lost and the pregnancy is destined from that point not to be. It might be that this lost information is not needed for many weeks, and the pregnancy will continue as normal until that time. When the needed information is not there, it is then that the baby dies and you begin to miscarry. Sometimes when this happens, the miscarriage doesn’t happen right away. This is called a ‘missed’ miscarriage and may not be picked up until some weeks later, following a slight loss or period-type pains.

Another cause might be that the baby did not implant, or bury itself, into the womb lining properly – once again, just due to bad luck.

These are the most common reasons that women miscarry. Not because of something you did or didn’t do, but just because of chance. Not because you drank alcohol, ate some unpasteurised cheese, or didn’t take folic acid. Certainly not because you had sex or didn’t rest enough. Whether you lay in bed from the day of your positive pregnancy test or went hang-gliding every day wouldn’t have changed things. Its nature’s way of making sure that when you do have a baby, it has the best chance for all of its life. Miscarriage does not mean that you won’t be able to get pregnant again.

How common is miscarriage?

It is worth considering how often pregnancy occurs on average each cycle. Studies looking at very sensitive pregnancy tests suggest that pregnancy will occur in at least 60% of natural cycles in fertile couples.

The risk of miscarriage decreases as pregnancy progresses. It is possible that as many as 50% of pregnancies miscarry before implantation in the womb occurs. Early after implantation, pregnancy loss rate is about 30% (ie this is still before a pregnancy is clinically recognised). After a pregnancy may be clinically recognised (between days 35-50), about 25% will end in miscarriage. The risk of miscarriage decreases dramatically after the 8th week as the weeks go by.

Recurrent miscarriages, is it just bad luck?

Many women miscarry more than once in their life. Considering the frequency of miscarriage, about 1 in 36 women will have 2 miscarriages due to nothing more than chance. Any miscarriages after that might prompt your doctors to suggest some tests to ensure that it isn’t happening for some other reason. If you’re worried have a chat with your GP or one of the Gynaecologists.

Miscarriage may be more common after a previous miscarriage, or less common following previously normal pregnancies. One London study from Prof. Regan’s Recurrent Miscarriage clinic found that the risk of miscarriage is related to the past pregnancy history in the following way:

First pregnancy 5%
Last pregnancy terminated 6%
Last pregnancy a live birth 5%
All pregnancies live births/td> 4%
1 previous miscarriage 20%
2 previous miscarriages 28%
3 previous miscarriages 43%

See also the Journal Watch item which reports on a recent study into unexplained recurrent miscarriage

What contributes to miscarriage?

The following is a list of things which can sometimes contribute to a miscarriage:

  • Multiple pregnancy.
  • Maternal age – there is a rise in miscarriage risk as maternal age increases. For women less than 35, the clinical miscarriage rate is 6.4%, for age 35-40 it is 14.7% and over the age of 40y it is 23.1%.
  • Poorly controlled diabetes (See gestational diabetes) – but not that which is well controlled.
  • Scleroderma – a soft tissue disease.
  • Fever over 100F.
  • Smoking – 30-50% increased risk (even after correction for socioeconomic status).
  • Previous contraceptive pill use results in a slight reduction in the risk of miscarriage.
  • Occupational exposure to solvents increases the risk of miscarriage.

How can I help prevent miscarriage next time?

As I mentioned above, the most common reasons for miscarriage can’t be helped, however you can prepare yourself for pregnancy. Taking in regular exercise, a healthy diet, reducing stress and getting your weight to within normal limits gives you something to concentrate on, and improves chances for long-term fertility. Certainly reducing your alcohol intake and stopping smoking will help, too. Remember to start taking folic acid to help normal development of the baby’s nervous system.

When can we start trying for a baby again?

Some couples decide that they want to begin trying for a pregnancy right away, while others feel that this is too soon and need time to get over this loss. There is no ‘right’ thing to do, and you have to go with your feelings.

We normally recommend that you wait for your first period after going home, and begin trying from then, if that’s what you decide. There is evidence that the risk of miscarriage in the next pregnancy is about 1.5 times higher if one cycle does not intervene the pregnancies. It is not imperative, however, and don’t worry if you find yourself pregnant before you even have a period – many successful pregnancies have started that way! In any case there’s no reason you can’t make love as soon as you feel ready. If you don’t want to get pregnant, talk to your GP soon about contraception suitable for you.

My partner has miscarried, how can I help her?

  1. Do let your genuine concern and caring show.
  2. Do be available… to listen or to help with whatever seems needed at the time.
  3. Do say you are sorry about what has happened and about their pain.
  4. Do allow them to express as much unhappiness as they are feeling and are willing to share.
  5. Do encourage them to be patient with themselves and not to expect too much of themselves, nor to impose any ‘shoulds’ on themselves.
  6. Do allow them to talk about their loss as much and as often as they want to.
  7. Do reassure them that they did everything they could and that it wasn’t their fault.
  8. Don’t let your own sense of helplessness keep you from reaching out.
  9. Don’t avoid them because you are uncomfortable. Being avoided by friends may add pain to an already painful experience.
  10. Don’t say that you know how they feel (unless you have experienced their loss yourself, and then you can be particularly supportive).
  11. Don’t say ‘you ought to be feeling better by now’ or anything which implies judgment about their feelings.
  12. Don’t tell them what they should feel or do.
  13. Don’t change the subject when they mention their loss.
  14. Don’t avoid mentioning their loss out of fear of reminding them of their pain (they won’t have forgotten).
  15. Don’t try to find something positive about the loss (eg. a moral lesson, closer family ties, etc).
  16. Don’t point out that at least they have their other….
  17. Don’t say that they can always have another…. (they wanted this one).
  18. Don’t say that they should be grateful for….
  19. Don’t make comments, which in any way suggest that the loss was their fault (there will be enough feelings of doubt and guilt already).


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