Recurrent miscarriages
LOSING pregnancies repeatedly can be a very emotional and traumatic experience. Almost 15 per cent of women who become pregnant will have a miscarriage at some time during their reproductive years. Recurrent miscarriages, also known as recurrent pregnancy loss (RPL), is defined as losing three or more consecutive pregnancies, and it affects less than one per cent of the population.
The risk of miscarriage increases with each successive pregnancy loss, but some studies show that a pregnancy ending with delivery of a live baby reduces the risk of miscarriage in the next pregnancy. Older women, however, may have a higher rate of pregnancy loss of both normal and abnormal embryos likely due to poor egg quality.
Most couples that have had a pregnancy loss usually want to know, “Doc, what caused it?” “Will it happen again?”
CAUSES
The cause of RPL is unknown in 50 per cent of patients. The known causes of RPL may be classified into four groups – anatomical, immunological, genetic and others.
ANATOMICAL FACTORS – CONDITIONS THAT CHANGE THE SHAPE OF THE INSIDE OF THE UTERUS/WOMB
Anatomical factors include the septate uterus, submucosal fibroids, cervical insufficiency or weakness, and intrauterine adhesions (scarring of the uterine lining). A septate uterus is one in which the uterine cavity is partitioned by a longitudinal septum/tissue and accounts for up to 60 per cent of the recurrent pregnancy losses. Submucosal fibroids are those that are found in the cavity and usually cause heavy and painful periods. Intrauterine adhesions are scar tissue within the uterine cavity. This scar tissue might have occurred after having had a dilation and curettage (D&C), especially if there was an associated infection of the uterus.
AN AUTOIMMUNE CONDITION WITH THE MOTHER
In this instance, the mother’s immune or infection fighting system attacks healthy tissue instead of abnormal areas. This is seen in conditions such as systemic lupus erythematosus (SLE), and antiphospholipid syndrome (APS). Uncontrolled diabetes may also cause early and late recurrent miscarriages. An Hba1c greater than eight per cent in early pregnancy increases the rate of pregnancy loss and abnormal foetuses. Patients with thyroid antibodies and diseases of the thyroid such as hyperthyroidism and hypothyroidism may be at risk for recurrent miscarriages.
GENETIC FACTORS
Genetic factors are abnormalities of chromosome number or structure, and they are the most frequent cause of early pregnancy loss, accounting for at least 50 per cent of such losses in multiple studies. Chromosomes are microscopic structures located inside the cells of the body. Each chromosome is passed from parents to offspring; the chromosome contains the specific instructions that make each living creature unique. There is an increased risk of RPL in first-degree relatives of women with unexplained RPL, and there is a higher rate of chromosomally abnormal embryos in young women with previously abnormal conceptions. Male factors may also be responsible for recurrent miscarriages in women whose male partner has abnormal sperm (example, fewer than four per cent normal forms and increased sperm DNA fragmentation). Advanced paternal age may also be a risk factor for miscarriage.
OTHER CAUSES INCLUDE:
1. Hyperprolactinaemia – high levels of prolactin, a hormone secreted from a part of the brain can also cause recurrent miscarriages.
2. Recently research has found that the lining of the womb in patients with recurrent miscarriages have fewer stem cells, suggesting there is a defect in the lining of the womb before the woman becomes pregnant. More research in this area is needed.
3. There is some association with RPL and environmental factors and stress. However, there is no high-quality evidence showing a relationship between RPL and occupational factors, stress, or low-level exposure to most environmental chemicals. Chemicals, which may be potentially harmful, include formaldehyde, pesticides, arsenic and mercury. To date, no infectious agent has been proven to cause RPL.
MANAGEMENT OF COUPLES WITH RPL INCLUDE
1. A complete history, thorough physical examination and special investigations. The special investigations usually consist of a diagnostic hysteroscopy or saline infusion hysteroscopy (SIS) to rule out any problems in the cavity of the uterus. Karyotyping, a unique form of genetic testing, is used to rule out genetic disorders and immunological testing is done to rule out conditions such as thyroid antibodies and the antiphospholipid antibody syndrome.
2. Couples with chromosomal problems should be referred for genetic counselling. The advice should include information about the probability of having a chromosomally normal baby, how to screen for any abnormalities in or before the pregnancy, and all the available treatment options.
3. Uterine abnormalities such as a septum, submucosal fibroid, and intrauterine adhesions are managed surgically. Operative hysteroscopy is usually effective in treating these conditions and may be performed as an outpatient procedure.
Inserting a cervical cerclage at approximately three months of gestation is the treatment of choice for cervical insufficiency.
Immunological conditions are treated medically, that is with drugs, by an immunologist and a gynaecologist.
Couples with genetic disorders may try the following options:
1. In vitro fertilisation and pre-implantation genetic diagnosis, egg or sperm donation, gestational surrogate or a combination of the above.
2. Lifestyle changes in couples with unexplained recurrent miscarriages have been shown to increase fertility potential. These changes include eliminating the use of tobacco, alcohol, caffeine and a reduction in weight for obese women.
At the end of the day, it is important to point out that up to 70 per cent of couples with unexplained recurrent pregnancy loss go on to have healthy babies.
Dr Michelle Bailey is a consultant OBGyn at Unit 10 Seymour Park, 2 Seymour Avenue, Kingston 5, and 6 West Medical, Old Harbour. She can be contacted at 927- 7436, 983-0240 or drmichellebailey@gmail.com.
