What is a Miscarriage?

Miscarriage is a pregnancy that ends spontaneously before 20 weeks, and effects one in every four women. 99% of foetal deaths occur in the first 13 weeks of pregnancy (the 1st trimester is 12 weeks), although you may not actually miscarry for some weeks after the baby dies. This is called a missed abortion. (The medical term for miscarriage is "abortion' and the baby is an "embryo' to the 8th week and a "foetus' after that.)

The chance of losing your first pregnancy is greater than later ones.

How common is miscarriage?

When considering this question, it is helpful to ask 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.

Why did it happen - was it my fault?

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.

What happens during miscarriage?

The symptoms you experience will depend on the cause of the miscarriage and how advanced the pregnancy was. Usually the foetus, placenta and blood from the uterus leave the body through the vagina. You may discover during a routine scan that there is no heartbeat, or even an empty foetal sac. Usually by the time bleeding begins your baby has already died.

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