Miscarriage

Miscarriage is the loss of a pregnancy before the age of viability (22-24 weeks of pregnancy).  Miscarriage is estimated to occur in at least 15% of confirmed pregnancies and thus is very common:  1 in 4 women will suffer at least one miscarriage.

Most miscarriages are due to the pregnancy having the wrong number of chromosomes. Chromosomes are the structures which carry our genes, There are 23 pairs of chromosomes (numbered 1 to 22, plus two sex chromosomes) in each cell.  Half the chromosomes come from our mother and half from our father.

Frequently a mistake happens during the development of a sperm or an egg, and one of them has the wrong number of chromosomes, so that the baby also has the wrong number of chromosomes.  The most well-known example of this is Down Syndrome, in which the affected baby or child has 3 copies of chromosome number 21 instead of 2 copies.

As women get older, their eggs are more prone to have abnormal numbers of chromosomes and hence the miscarriage risk and the risk of Down Syndrome increases with age of the woman.

Most chromosome abnormalities in pregnancies are sporadic and tend not to recur with different pregnancies.  Very rarely, there is a genetic problem and affected pregnancies can recur, leading to recurrent miscarriages.  Genetic problems can be screened for in both partners to determine this risk.

Recurrent Miscarriage

Recurrent miscarriage is defined as the loss of three or more consecutive pregnancies. Around 1% of couples experience this devastating problem. In most cases, no definite reason is found and most couples will go on to have successful pregnancies in the future.  Most couples do not need any particular treatment, apart from supportive care with regular ultrasound scans.

However, there are recognised factors which are thought to cause recurrent miscarriage, as follows:

1. Genetic abnormalities: You and your partner will be screened for this
2. Abnormalities of the womb: You will have a 3D ultrasound of your womb cavity or a hysteroscopy to determine whether there is an abnormality in the shape of the womb.
3. Antibodies: You will have blood tests to determine whether you have antiphospholipid syndrome.  If you do, you will be advised on treatment.
4. Blood clotting problems:  You will have blood tests to check for this and treatment will be advised if there is a problem.
5. Hormonal factors:  You will have blood tests to check your thyroid function and ovarian function.
6. Psychological and emotional factors:  Supportive treatment will ensure you are feeling confident regarding your next pregnancy, which helps to reduce the risk of miscarriage.