Recurrent miscarriage at a glance
- Recurrent miscarriage occurs when a woman has two or more consecutive clinical miscarriages before the 20th week of pregnancy, according to the American Society for Reproductive Medicine (ASRM).
- Recurrent miscarriage, also known as recurrent pregnancy loss, most often results from genetic or chromosomal abnormalities of the embryo that happen by chance.
- Recurrent miscarriage may indicate an underlying cause of infertility, such as abnormality of the uterus.
- Only about 1 percent of pregnant women will have recurrent miscarriage, according to the American College of Obstetricians and Gynecologists (ACOG).
- For recurrent miscarriages due to chromosomal issues, patients may consider preimplantation genetic testing during in vitro fertilization (IVF) to identify defect-free embryos to implant, increasing the chance of successful pregnancy.
What is recurrent miscarriage?
When a woman experiences two or more consecutive miscarriages, she has experienced recurrent miscarriage, also referred to as recurrent pregnancy loss. Technically, the pregnancy losses must be “clinical miscarriages,” meaning they occurred before the 20th week of pregnancy and residual tissue related to pregnancy or previous ultrasound evidence of pregnancy confirms the pregnancy.
Miscarriage is fairly common, and about 12-15 percent of clinical pregnancies end in miscarriage. Indeed, many women have miscarriages with no signs or symptoms and do not ever know they have lost a pregnancy.
Only about 1 percent of women will have a recurrent miscarriage, according to ACOG, which reports that no cause is identified in 50-75 percent of recurrent miscarriage cases. Of those women, 65 percent eventually will have a successful pregnancy.
ACOG recommends that women who have three consecutive miscarriages have a physical examination and testing for possible causes.
Signs & symptoms
Women having a miscarriage or recurrent miscarriage may experience vaginal bleeding, notice lack of movement or sound from the fetus, and their breasts may lose their fullness and tenderness. The symptoms are identical for both miscarriage and recurrent miscarriage. Women should keep track of their blood loss and report such signs to their doctor.
Sometimes women experience no signs or symptoms that they are having or have had a miscarriage or a recurrent miscarriage.
What causes recurrent miscarriage?
ACOG says about 60 percent of all miscarriages occur by chance due to the embryo receiving an abnormal number of chromosomes from one of the parents. This holds true for recurrent miscarriages as well.
This is not caused by an underlying disease. The risk of this increases with the age of the mother, probably due to the increase in risk for chromosomal abnormalities in their embryos. A woman’s risk of miscarriage also increases with the number of miscarriages she has had.
In a small number of couples experiencing recurrent pregnancy loss, chromosomal translocation occurs. This means a part of one parent’s chromosome has transferred to a different chromosome. This often results in the egg or sperm of the parent with translocation having abnormal chromosomes, causing the miscarriage.
Parents with chromosomal translocation may want to consider preimplantation genetic diagnosis (PGD). This is done in conjunction with IVF and involves genetic testing of the resulting embryos to identify abnormal chromosomes. Only normal embryos are then chosen for implantation, increasing the chance of successful pregnancy.
Other causes of recurrent miscarriage (and miscarriage) include:
- Anatomical problems, such as a misshapen uterus (womb) or cervix
- Polycystic ovary syndrome (PCOS) can cause noncancerous growths that disrupt the ovaries and ovulation
- Fibroids and polyps are also noncancerous growths and these can invade the uterus, impeding embryo implantation
- The autoimmune disorder antiphospholipid syndrome (APS) can cause the body’s immune system to attack agents necessary for blood clotting and healthy pregnancy
- Hormone issues, such as an overactive or underactive thyroid gland or too much prolactin from the pituitary gland
- Infections, such as bacterial infections from chlamydia and herpes or from the viral infection German measles (rubella), can alter the fetus’ development
- Excessive alcohol or caffeine consumption, smoking, illicit drug use and being overweight or obese
- Asherman’s syndrome, which results from scar tissue in the uterus.
Diagnosis & treatment of recurrent pregnancy loss
Diagnosis generally involves a thorough physical examination, review of past pregnancies and a detailed medical history. Other diagnostic measures can include imaging tests to assess structural issues, blood testing for immune system issues and genetic testing for suspected chromosomal issues.
The cause of the recurrent miscarriage will direct the physician and patient in selecting the appropriate treatment. These include:
- Genetic counseling and PGD during IVF can increase pregnancy chances for parents with chromosomal problems
- Surgery may be used to correct structural issues and to remove lesions, polyps, scar tissue or fibroids
- Medications can correct hormonal imbalance issues
- Blood thinners can relieve APS issues
- Lifestyle changes such as reducing alcohol consumption, smoking cessation, weight loss and ending drug use.