Miscarriage is a devastating event, whether it happens once or multiple times. Unfortunately, it is not uncommon, with approximately only 30% of conceptions resulting in a live birth. Many women have either experienced a miscarriage themselves or know other women who have experienced a miscarriage. However, recurrent miscarriage, defined as 3 consecutive pregnancy losses before a gestational age of 20 weeks, is less common, affecting around 1–2% of women.
So, what causes recurrent pregnancy loss?
Currently, there are a small number of accepted causes for recurrent pregnancy loss, such as parental chromosomal abnormalities, untreated hypothyroidism, anatomical abnormalities of the uterus (such as fibroids or uterine septum), uncontrolled diabetes mellitus, poor egg quality due to advanced maternal age, and antiphospholipid antibody syndrome. Other potential causes include infections, endocrine disorders (such as luteal phase defect and polycystic ovarian syndrome), an acquired and/or heritable blood clotting disorder, environmental factors, and immunologic abnormalities.
So, as you can see, there are many possible causes of recurrent pregnancy loss and your healthcare provider will run a battery of tests to try and determine what is causing your pregnancy losses.
Diagnosing recurrent pregnancy loss
First, your doctor will take a detailed medical, surgical, genetic, and family history and will also perform a physical examination. The uterus will often be examined, either with an ultrasound, magnetic resonance imaging, X-ray (a hysterosalpingogram), or via a hysteroscopy. Testing for antiphospholipid antibodies will be performed and if you have a family history of clotting disorders, you will be tested for inherited thrombophilias. In addition, you may undergo hormone testing, including thyroid function tests as well as tests for levels of thyroid antibodies, prolactin and hormones such as follicle-stimulating hormone and anti-Mullarian hormone which can give you an idea of how well your ovaries are functioning. Diabetes testing will be conducted if the doctor suspects you are at risk for diabetes or if you have symptoms of diabetes.
What treatment is available for recurrent pregnancy loss?
The treatment for recurrent pregnancy loss depends on what the underlying cause is found to be. If you or your partner is found to have chromosomal abnormalities, you will be given the option to undergo genetic testing in your next pregnancy, such as amniocentesis or chorionic villus sampling. Or alternatively, you may decide to undergo in-vitro fertilization with pre-implantation genetic diagnosis of the resulting embryos before they are implanted. If a uterine abnormality is found, such as fibroids, you will be given the option of surgery. Specific medications can be given if you are suspected of having antiphospholipid syndrome, a thyroid condition, or diabetes, or an endocrine disorder.
However, no matter the results of the diagnostic work-up, the chance for a subsequent successful pregnancy is high: around 71% if an abnormality is detected and around 77% if no abnormality is found.
