Recurrent (repeated) miscarriages is having had at least 2 miscarriages.
A miscarriage is the loss of a fetus before 20 weeks of pregnancy. Each miscarriage should be carefully reviewed by a health care professional to determine if evaluation of a woman or a couple may be appropriate.
Recurrent miscarriages may be caused by problems in a woman, man, fetus, or placenta.
Chromosome abnormalities may cause about half of recurrent miscarriages.
Causes of Recurrent Miscarriage
The problem causing recurrent miscarriages may be in a woman, man, fetus, or placenta.
In a woman, common problems that cause recurrent miscarriages include
Abnormalities in the uterus or cervix, such as polyps, bands of scar tissue (adhesions), and cervical insufficiency
Poorly controlled chronic disorders, such as an underactive thyroid gland (hypothyroidism), an overactive thyroid (hyperthyroidism), diabetes, high blood pressure, and chronic kidney disease
If women have a disorder that causes blood to clot too easily (such as antiphospholipid syndrome), they may have recurrent miscarriages that occur after 10 weeks of pregnancy, The reason may be blood clots that damage the placenta and thus decrease the flow of nutrients from a woman to a fetus.
A miscarriage is more likely if women have had a miscarriage in a previous pregnancy. The more miscarriages a woman has had, the higher the risk of having another miscarriage. The risk of having another miscarriage also depends on what the cause is, but overall, women who have had several miscarriages have about a 1 in 4 chance of having a miscarriage in a later pregnancy.
Chromosome disorders in a male partner may also cause recurrent miscarriages. Having certain abnormalities in semen increases the risk of miscarriage. Whether older age (over 35) of a male partner increases risk of a miscarriage is unclear.
In a fetus, common causes include
Chromosome or genetic abnormalities
Structural abnormalities (birth defects)
Chromosome abnormalities in a fetus may cause 50% of miscarriages. Miscarriages due to chromosome abnormalities are more common during early pregnancy.
Problems with the placenta include chronic disorders that are poorly controlled, such as systemic lupus erythematosus (lupus) and chronic high blood pressure.
The cause of recurrent miscarriages cannot be determined in up to half of women.
Diagnosis of Recurrent Miscarriage
A doctor's evaluation
Tests to identify the cause
If women have had 2 or more miscarriages, they may want to see a doctor before they try to become pregnant again. The doctor can check them for genetic or structural abnormalities and for other disorders that increase the risk of a miscarriage. For example, doctors may do the following:
Genetic tests to check for chromosomal abnormalities in both parents
An imaging test (such as ultrasonography, sonohysterography, or hysterosalpingography) to look for structural abnormalities
Blood tests to check for certain disorders, such as antiphospholipid syndrome, diabetes, hormone abnormalities, and thyroid disorders
The diagnosis of recurrent miscarriage is based on having had 2 or more miscarriages.
Treatment of Recurrent Miscarriage
Treatment of the cause if possible
Some causes of recurrent miscarriages can be treated, making a successful pregnancy possible.
