Known causes of Recurrent Miscarriage:
Antiphospholipid syndrome (APS)
- This blood clotting problem is the most important treatable cause of recurrent miscarriage. It happens when your immune system makes abnormal antibodies that attack fats called phospholipids in your blood.
- This makes the blood more ‘sticky’ and likely to clot, which is why APS is sometimes called ‘sticky blood syndrome’.
- It is also known as ‘Hughes syndrome’ after the expert who named it. It is not clear why these antibodies cause miscarriage.
- They may stop the pregnancy embedding properly in the uterus (womb); or they may interfere with blood flow to the placenta, which supports the baby.
- APS can also lead to problems in later pregnancy, including the baby not growing enough, pre-eclampsia or stillbirth.
Other blood clotting problems
Some inherited blood clotting disorders can cause recurrent miscarriage, particularly after 14 weeks. These include:
- Factor V Leiden
- Factor II (prothrombin)
- Gene mutation
- Protein S deficiency
- The chromosomes in every cell of your body carry hereditary information in the form of genes.
- Everyone has 23 pairs of chromosomes, and 22 of these are the same in men and women. The 23rd pair is different because they determine gender.
- Men normally have one X and one Y chromosome and women two X chromosomes.
- A baby inherits half its chromosomes from each parent.
- About half of all miscarriages happen because the baby’s chromosomes are abnormal. This is not usually an inherited problem: it happens when the egg and sperm meet or soon after the egg is fertilised.
- The older you are the more likely this is to happen. Much less commonly (in less than five in one hundred couples with recurrent miscarriage), one partner carries a chromosomal defect called a ‘balanced translocation’. This doesn’t cause a problem for the parent, but it can be passed on to the baby as an ‘unbalanced translocation’.
- This means that some genetic information is duplicated and some is missing.
- It is also known as ‘incompetent cervix’
- Some women, probably less than one in a hundred, have a weakness in the cervix that allows it to dilate too early.
- This is a known cause of late (second trimester) miscarriage.