Unfortunately, recurrent miscarriages are common. According to BMC Pregnancy and Childbirth, each time a patient miscarries, their chances of another miscarriage increase. Repeated pregnancy loss can be especially frustrating for women with secondary infertility who have successfully given birth in the past.
But there is good news: Thanks to a variety of tests, it's possible to identify the cause of recurrent miscarriages — and most women who miscarry eventually go on to have a healthy pregnancy. Understanding how to explain the common causes of miscarriage to patients can help you support them in working toward a healthy pregnancy and childbirth.
Chromosomal Abnormalities
According to Translational Pediatrics, chromosomal abnormalities are the most common cause of pregnancy loss and recurrent miscarriages. As the cells of the sperm and egg divide, random errors can happen in one or more of the 23 pairs of chromosomes. The most common type of chromosome abnormality is aneuploidy: too many or too few chromosomes. Aneuploidy is more likely to occur in women who become pregnant at a later age.
It's best to refer patients with genetic causes of miscarriage to a genetic counselor. They may perform tests such as chromosome karyotyping, a carrier test, a products of conception test and preimplantation genetic testing during an IVF cycle to help patients determine if their recurrent miscarriages are genetic.
Uterine Abnormalities
Polyps, fibroids and adhesions or a bicornuate, unicornuate, septate or arcuate uterus may also be the cause. To diagnose abnormalities, a reproductive endocrinologist might perform a sonohysterogram (SHG) or saline infusion sonography (SIS). Minimally invasive, cost-effective ultrasound allows doctors to identify scar tissue, abnormal growths and other irregularities in the uterine lining and visualize the shape of a patient's uterus.
ultrasound of septate uterus
Uterine polyp
After the ultrasound, the physician should share their findings using images and explain the next steps to the patient. Depending on the type of abnormality, a doctor may recommend corrective surgery or a wait-and-see approach.
Hematology
Blood clotting conditions such as factor V Leiden may explain up to 65 percent of recurrent miscarriages, according to a study published in Clinical and Applied Thrombosis/Hemostasis.
Most often, these conditions will appear on a comprehensive genetic screening test. However, additional testing may be needed, so it's best to refer the patient to a hematologist for further evaluation and discussion.
Infection
The most common infectious cause of recurrent miscarriages is chronic endometritis, which is diagnosed via a uterine lining biopsy taken during hysteroscopic surgery. Thankfully, if the test comes back positive, the treatment is a simple course of antibiotics. A study published in Reproductive Science found that 78.4 percent of women with chronic endometritis became pregnant within a year of treatment.
Autoimmunity
A compromised immune system sometimes prompts a patient's body to attack an embryo as a foreign entity. Many autoimmune diseases and autoimmune-related disorders — such as Celiac disease and lupus — may cause recurrent miscarriages.
Testing starts with a blood test for common disorders, as well as natural killer cells, antiphospholipid antibodies and antithyroid antibodies. If any of these tests comes back positive, doctors should refer patients to a reproductive immunologist for further evaluation.
Endocrine Disorders
Finally, women with endocrine-related disorders such as thyroid conditions and diabetes are at risk for recurrent pregnancy loss. Most endocrine conditions are diagnosed with blood tests. Once a diagnosis is made, physicians should refer patients to an endocrinologist, preferably one who specializes in preconception and pregnancy.
While some miscarriages remain unexplained, physicians have many diagnostic tools at their disposal. Once a cause is discovered, they can offer definitive next steps and give patients hope that a successful pregnancy is likely right around the corner.
5 week pregnancy
A 5-week intrauterine pregnancy.
