Pregnancy loss can be medically and emotionally difficult. Many losses are associated with chromosome-number changes that arise spontaneously in the embryo and are not caused by something either parent did or did not do. In recurrent pregnancy loss, genetic evaluation may help explain a loss and support accurate counselling for a future pregnancy.
How is recurrent pregnancy loss defined?
The 2026 ASRM committee opinion defines recurrent pregnancy loss as two or more spontaneous pregnancy losses, excluding ectopic and molar pregnancies. Evaluation may therefore be considered after the second loss. Age, gestational timing of losses, family history and previous test results still shape the individual plan.
Which sample is assessed first?
Current ASRM guidance recommends offering chromosome evaluation of pregnancy-loss tissue, when feasible, to people experiencing a second miscarriage or with a history of recurrent loss. Array-based chromosome testing may show whether a sporadic aneuploidy contributed to the loss and can help avoid unnecessary investigations.
Correct tissue sampling and assessment for maternal-cell contamination are important. No method detects every genetic change; a normal result cannot exclude non-genetic causes or changes outside the method’s scope.
When are parental karyotypes requested?
Parental karyotyping may be offered when an unbalanced structural chromosome rearrangement is found in loss tissue or when chromosome testing of the loss is unavailable. A karyotype can identify large balanced rearrangements, such as a translocation or inversion, in an otherwise healthy parent.
A balanced rearrangement does not mean that every pregnancy will end in loss. Chance depends on the chromosomes, breakpoints and which parent is the carrier. Individual risk and reproductive options require genetic counselling.
Is genetic assessment enough on its own?
No. Recurrent loss is often multifactorial. Assessment of the uterine cavity and, in selected circumstances, antiphospholipid antibodies, thyroid function and other clinical factors may also be appropriate. Inherited thrombophilia panels, MTHFR testing and unsupported immune tests are not routine solutions for every patient. Evaluation should be evidence-based and stepwise.
What can be discussed after the result?
- If a sporadic aneuploidy is found, recurrence chance can be discussed in relation to age and history.
- If a parent has a balanced rearrangement, natural conception, prenatal diagnosis and PGT-SR in suitable cases may be considered.
- If the result is not explanatory, assessment for non-genetic causes continues.
- Psychological support and patient preferences should remain part of care.
Plan genetic evaluation with the appropriate sample and method
For information about chromosome analysis of pregnancy-loss tissue, parental karyotyping and method selection, explore our Cytogenetics service.
