Alternative Names
miscarriages; spontaneous abortions; stillbirths
Symptoms & Characteristics
Pregnancy loss or the birth of a stillborn child can result from many different causes including genetic causes, non-genetic causes, or a combination of both. Recurrent pregnancy loss is defined as two or more losses in a couple. Different types of evaluations and tests are often needed to establish a cause (if possible). Detailed pregnancy, personal and family histories are assessed in order to prioritize which evaluations and tests will likely be the most informative.
Evaluations may include different specialties such as genetics, maternal fetal medicine, reproductive endocrinology, and gynecology. Evaluations and tests may take time to complete, which can often be stressful for parents many of whom are already grieving. Much of the time, even after numerous evaluations and tests, a cause is still not found.
Treatment
Treatment is dependent upon the cause (if known).
How Common Is It?
It is estimated that up to 50% of all pregnancies end in miscarriage. However, many pregnancies are lost very early before the pregnancy is even recognized.
Genetics & Inheritance
Both genetic and non-genetic factors play a role in pregnancy loss and stillbirths. Some non-genetic causes may include:
- Drinking alcohol during pregnancy
- Environmental exposure to harmful toxins, chemicals, or medications
- Uterine abnormalities (like bicornate uterus, incompetent cervix, and fibroids)
- Placental abruption or bleeding
- Uncontrolled maternal diabetes or some other metabolic conditions
There are also various genetic causes of pregnancy loss and stillbirths. Some of the more common genetic causes may include:
A parental chromosome abnormality (especially a structural rearrangement in chromosome material called a chromosome translocation)
- Sometimes a parent can have a rearrangement of genetic material in their chromosomes but no actual loss or gain of genetic material. This is called a balanced chromosome translocation. Although this parent is healthy with no physical or mental problems, they have an increased risk to have a conception with extra or missing genetic material. This can result in pregnancy losses, a stillborn child or a living child with physical and developmental problems.
- In about 5% of couples with recurrent pregnancy losses, one of them has a chromosome translocation. Their risk to have another conception with a chromosome abnormality is usually increased, although a healthy pregnancy outcome may also be possible. Genetic counseling is very important, as recurrence risks differ depending on the gender of the parent with the chromosome translocation as well as what genetic material is actually rearranged.
- If both parents have normal chromosomes, they still have a risk to have a conception with a chromosome abnormality. However, this risk is typically based on the women's age at delivery.
A fetal chromosome abnormality (such as a chromosome translocation, extra or missing chromosomes or other chromosome abnormalities)
- About 60% of all first trimester pregnancy losses are due to a fetal chromosome abnormality, the majority of which happen by chance and are not inherited from the parents.
- Less commonly, chromosome abnormalities are inherited from a parent.
A genetic condition in fetus
- Sometimes, instead of having a chromosome abnormality, the fetus has a mutation in a particular gene or a deletion or duplication of a small number of genes.
- A diagnosis of a genetic condition can be very difficult; especially as hundreds of genetic conditions have been associated with pregnancy loss or stillbirth. Autopsy and pathology may help prioritize which genetic tests (if any) can be performed.
A genetic blood clotting disorder called thrombophilia (in females)
- Mutations in genes that increase risk to form blood clots have been associated with recurrent pregnancy loss. In the past, genetic testing consisted of a thrombophilia panel which included three genes, Factor V Leiden, Prothrombin II, and MTHFR. There is currently a debate if genetic testing for MTHFR is clinically useful and some physicians and labs no longer offer MTHFR as part of their thrombophilia panels.
There are some reproductive options for people who have chromosome abnormalities or genetic conditions that cause recurrent pregnancy loss and stillbirths. Some of these options may include:
- In vitro fertilization (IVF) can be used in conjunction with preimplantation genetic diagnosis (PGD). PGD is a technique used to identify genetic defects in embryos before transferring them into the uterus.
These decisions are very personal and complex and are best made with the help of a specialist who not only fully understands all of the options, but is also understanding of a couple's specific concerns. Genetic counseling with a trained genetic professional may be beneficial along with other specialist consultations.
Genetic Testing
Clinical genetic testing for recurrent pregnancy loss and stillbirths can be broken down two categories: fetus/stillbirth testing and parental testing.
Clinical genetic testing for a fetus or stillborn is only available in perinatal centers or hospitals. This testing may include:
- Specialized genetic testing for a specific genetic condition if indicated by autopsy, family history or pathology reports
Parental clinical genetic testing is often available as part of a gender-specific Recurrent Pregnancy Loss panel. This testing may include:
- Genetic testing for blood clotting disorders (for females only)
Parental genetic testing for recurrent pregnancy loss/stillbirths is available online (over the internet) or through an in person genetic consultation. Go to the Tests tab to link to the best providers, compare providers and read provider reviews or use our find a genetic professional directory to locate a trained genetic professional in your area.
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