Miscarriages can run in families, but most don’t. About half of all first-trimester miscarriages result from random chromosomal errors in the embryo, the kind that happen spontaneously and aren’t inherited from either parent. That said, several genuinely heritable conditions can raise miscarriage risk across generations, from blood clotting disorders to structural differences in the uterus to hormonal conditions like PCOS. Whether a family pattern reflects shared genetics or shared bad luck depends on the specific situation.
Why Most Miscarriages Are Not Inherited
The single biggest cause of early pregnancy loss is aneuploidy, where the embryo ends up with the wrong number of chromosomes. This accounts for roughly 50% of first-trimester miscarriages. Aneuploidy is random and unpredictable. It happens during cell division in the egg or sperm and isn’t something passed down through family lines. A woman whose mother or sister had a miscarriage from this cause has no elevated risk herself.
Age is the main driver of these random errors. Miscarriage risk is lowest around age 25 to 29, sitting near 10%. It climbs to about 17% by the late 30s, 32% by the early 40s, and over 53% after age 45. So if miscarriages seem to cluster in a family, the first question worth asking is whether they happened at similar maternal ages. A pattern that looks genetic may simply reflect the biology of egg quality over time.
Inherited Blood Clotting Disorders
One of the clearest genetic links to recurrent miscarriage involves inherited thrombophilias, conditions where blood clots more easily than it should. The most common is Factor V Leiden, a gene mutation carried by about 5% of people of European descent. Women with one copy of the mutation are two to three times more likely to experience recurrent miscarriages, particularly losses in the second or third trimester when blood flow to the placenta becomes critical. Those who inherit two copies (one from each parent) face a higher risk still.
Because Factor V Leiden follows a straightforward inheritance pattern, it absolutely runs in families. If your mother carried the mutation, you have a 50% chance of inheriting it. This is one of the scenarios where a family history of multiple pregnancy losses, especially later losses, points toward a testable, treatable genetic cause.
Chromosomal Translocations
In 3 to 5% of couples with recurrent miscarriage, one partner carries what’s called a balanced translocation. This means pieces of two chromosomes have swapped places. The carrier is perfectly healthy because all their genetic material is present, just rearranged. But when they produce eggs or sperm, some will end up with extra or missing chromosome segments, creating embryos that can’t develop normally.
Balanced translocations are inherited. A parent who carries one has a significant chance of passing it to their children, who may then face the same pattern of pregnancy loss. This is one reason genetic testing of miscarriage tissue is recommended after two or more consecutive losses. If a translocation is identified, it changes the conversation about future pregnancies and available options.
Paternal Genetic Factors
The father’s genetics matter too. Male carriers of chromosomal translocations can produce sperm with imbalanced genetic material, leading to embryos that miscarry. Beyond translocations, elevated sperm DNA fragmentation has been consistently linked to recurrent pregnancy loss. Small deletions on the Y chromosome, particularly in regions tied to fertility, are also associated with increased miscarriage risk. These paternal factors can be inherited by sons, potentially creating a pattern of pregnancy loss that runs through the male side of a family.
PCOS and Hormonal Conditions
Polycystic ovary syndrome affects 6 to 15% of women of reproductive age and significantly raises miscarriage risk. Early pregnancy loss occurs in 30 to 50% of women with PCOS, compared to 10 to 15% in the general population. The elevated risk comes from a combination of insulin resistance and higher-than-normal testosterone levels, both of which can disrupt the hormonal environment an early pregnancy needs to survive.
PCOS has a strong hereditary component. It clusters in families, and daughters of women with PCOS are at substantially higher risk of developing it themselves. This means a family pattern of early miscarriages could trace back to PCOS running through generations, even if no one in the family was formally diagnosed. Many women with PCOS don’t know they have it until they start trying to conceive.
Uterine Structural Differences
Congenital uterine malformations, where the uterus forms with an unusual shape during fetal development, are found in up to 16.7% of women with recurrent miscarriage. These include a septate uterus (divided by a wall of tissue) or a bicornuate uterus (heart-shaped). Both can interfere with implantation or restrict the space available for a growing pregnancy.
These structural differences have a hereditary component. Research analyzing nearly 1,400 cases found that about 10% of uterine malformations could be attributed to familial association. First-degree relatives of affected women had a risk roughly 12 times higher than the general population. Siblings showed the strongest association, with a relative risk nearly 13 times the baseline. Several specific genes involved in reproductive tract development have been identified, and the inheritance pattern appears to follow an autosomal dominant model with incomplete penetrance, meaning you can carry the gene without necessarily developing the malformation.
When Family History Warrants Testing
Recurrent pregnancy loss is clinically defined as two or more consecutive miscarriages (in the U.S.) or three or more (in the U.K.). After two consecutive losses, guidelines recommend genetic evaluation of miscarriage tissue to look for chromosomal abnormalities. The CDC lists two or more miscarriages as a reason for referral to genetic counseling, along with a previous pregnancy affected by a genetic condition or a family health history that raises concern.
If miscarriages have affected multiple women in your family, or if a family member has been diagnosed with a balanced translocation, clotting disorder, or uterine malformation, that information is worth sharing with a provider. Genetic counseling can help sort out whether the pattern reflects something testable or whether it falls within the range of normal statistical variation. A single miscarriage in your mother’s history and one in yours doesn’t necessarily signal a genetic link. Two or three losses across generations, especially with similar timing in pregnancy, paints a different picture.
For conditions like Factor V Leiden, testing is a simple blood draw. Chromosomal analysis requires a blood sample from both partners. Uterine shape can be evaluated with imaging. Many of these causes, once identified, have management strategies that substantially improve the odds of a successful pregnancy.