A recurrent miscarrage is when there is a loss of three or more pregnancies in a row. This only affects approximately 1% of couples.
Common causes include chromosomal complications, structural irregularities in the uterus, or issues with the immune or endocrine system.
In some cases an irregularity in the uterus, whether it be the shape or the weakness of the lining, can cause a miscarriage. Women can either be born with these irregularities or they can develop over time.
Causes of recurrent miscarriages are most commonly unknown, however factors that affect the mother are more likely, for example:
- Responses by the immune system that can result in a disruption to the implantation of the egg.
- Hormone imbalances at the time of conception or early on in the pregnancy.
- Blood-clotting problems.
- An increase in maternal age can cause an increase in the risk of a spontaneous miscarriage.
- Chronic diseases such as diabetes or thyroid disease.
Some causes of recurrent miscarriage are treatable and the couple can proceed to have a healthy pregnancy, however some are not, and the risk of continuing miscarriages is high.
Factors that may increase the risk of miscarriage include:
- Increased maternal age:
- Women who are 35 have a 20-25% risk
- Women who are 40 have a 40-50% risk
- Women who are 45 or older have an 80% risk
- Previous miscarriages – women with two or more recurrent miscarriages are at a higher risk
- Diabetes or other chronic conditions
- Uterine or cervical malformations or conditions
- Ingestion or inhalation of cigarette smoke, alcohol or illicit drugs
- Weight – the risk of miscarriage is increased if the mother is under or overweight.
- Invasive prenatal tests – tests such as amniocentesis or chorionic villus sampling carry a small risk of miscarriage.
If you have experienced recurrent miscarriages, consideration must be taken to assess your health and the underlying causes of your previous pregnancy losses before an attempt is made to get pregnant again.
A blood test is advisable to attempt to detect any issues with your immune or endocrine system which could be a factor in the consecutive miscarriages.
A blood test is advisable to determine whether genetic irregularities, by either you or your partner, is a factor, and a karyotype analysis may be performed. A test on the tissue sample from the previous miscarriages may also be helpful.
Procedures such as an ultrasound, hysteroscopy, hysterosalpingography, or sonohysterogram, can be used to determine the structural integrity of the uterus, uterine lining, and uterine tubes, as well as detect any abnormalities or irregularities that could be a factor in the pregnancy loss. An MRI may be performed to evaluate the presence of a uterine septum which may be a cause of the miscarriage.
Most women with recurrent miscarriages go on to have successful future pregnancies. If the cause for the recurrent miscarriage is discovered, treatment may be adjusted accordingly.
Genetic counselling is advised for couples with genetic irregularities.
Surgery may be performed on women who have a uterine irregularity.
For women diagnosed with anti-phospholipid syndrome, medications can be purchase to decrease blood clot development and to reduce the threat of further pregnancy loss. For women diagnosed with thyroid dysfunction or diabetes, medication can be prescribed to help manage this.