What causes recurrent miscarriage?
There are many factors that can cause recurrent miscarriage. More than half of miscarriages in the first 13 weeks of pregnancy are caused by problems with the baby's chromosomes — problems with the number or the structure of the chromosomes, or with the genes they carry. In a small number of cases, problems with the parents' chromosomes can cause recurrent miscarriage. There are tests to establish whether such problems are a factor. In addition, medical conditions in the woman, or problems with her uterus, can cause recurrent miscarriage. The following maternal medical conditions have been linked to an increased risk of recurrent miscarriage:
- Lupus and other autoimmune diseases
- Heart disease
- Severe kidney disease, particularly when associated with high blood pressure
- Diabetes
- Thyroid disease
- Infection in the uterus
- Polycystic ovary syndrome
- Antiphospholipid syndrome, a disorder of the immune system
- Hormonal imbalances
- Blood disorders
Several problems of the uterus are associated with recurrent miscarriage. Most are not common:
- Defects present from birth, such as a uterus divided into two parts by a wall of tissue (a septate uterus).
- Benign growths in the uterus, such as fibroids, which are made of muscle tissue.
- A cervix that begins to widen and open too soon, in mid-pregnancy, with no signs of pain or labor.
How is the cause of recurrent miscarriage established?
To find the cause of recurrent miscarriage, you will be asked about your medical history and your previous pregnancies. A full physical examination may be done, including a pelvic examination. You may also be offered genetic counselling. You may need certain tests as well:
- Blood tests to detect any problems with hormones or with the immune system.
- Chromosome testing of both you and your partner, or of the tissue from the miscarriage if it is available.
- Tests to detect a possible infection of the uterus.
Tests can also be done to help detect problems in the uterus:
- Hysterosalpingography — an X-ray of the uterus and fallopian tubes is taken after a small amount of dye has been injected into them.
- Hysteroscopy — a thin, lighted device is inserted through the vagina and the cervix to see inside the uterus.
- Ultrasound — sound waves are used to create an image of the internal organs.
- Sonohysterography — a transvaginal ultrasound is used to view the uterus. A saline solution is injected into the uterus to help expand it for a better view.
What can I do to plan a future pregnancy?
If you have had recurrent miscarriages, you should plan ahead. Future pregnancies should be planned, diagnosed early and monitored carefully. You may be able to improve your chances of a successful pregnancy in future by doing a number of things:
- Have a full medical check-up before trying to become pregnant again.
- If you think you may be pregnant, see your gynecologist straight away.
- Follow your gynecologist's advice.
- Keep a healthy lifestyle by eating healthy foods, exercising and avoiding alcohol, tobacco and drugs.