Description

Parental Chromosome Testing (Karyotype) for Recurrent Miscarriage

A parental chromosome test, also known as a karyotype, looks for structural chromosome rearrangements that may be carried by an otherwise healthy parent and may increase the risk of recurrent miscarriage or affect future pregnancies.

One example is a balanced translocation, where chromosome material is rearranged but no genetic material is lost or gained in the parent. A carrier is usually healthy, but some eggs or sperm may contain an unbalanced chromosome arrangement, which can lead to miscarriage or, less commonly, an affected pregnancy.

You can read more in our guide to Understanding Robertsonian Balanced Translocation.

Who may benefit from parental chromosome testing?

Parental karyotyping is not required for every couple who has experienced miscarriage. It is usually considered where there is a clinical reason to suspect an underlying chromosome rearrangement.

This may include:

• recurrent miscarriage
• a previous pregnancy affected by a chromosome abnormality
• an abnormal chromosome result from pregnancy tissue
• a relevant family history of chromosome rearrangements or genetic conditions
• previous pregnancy or fertility history that raises concern about a possible inherited chromosome abnormality

Testing is generally performed for both partners when clinically appropriate.

If you are unsure whether parental chromosome testing is appropriate for you, a Specialist Miscarriage Consultation can help review your history and determine which investigations are most relevant.

What does the test look for?

A karyotype examines the number and structure of the chromosomes.

It can identify larger chromosome abnormalities such as:

• balanced translocations
• Robertsonian translocations
• inversions
• certain large chromosome gains or losses
• other structural chromosome rearrangements

A normal parental karyotype does not exclude all genetic causes of miscarriage, but it can help rule out an important inherited cause of recurrent pregnancy loss.

Why can this matter for future pregnancies?

Unlike many tests performed after miscarriage, parental chromosome testing assesses a genetic characteristic that remains relevant for future pregnancies.

If one partner is found to carry a balanced chromosome rearrangement, the result may help explain previous pregnancy losses and can provide useful information about the risk of miscarriage or chromosome imbalance in future pregnancies.

Depending on the result, further discussion may include:

• referral for genetic counselling
• options for testing in a future pregnancy
• chorionic villus sampling or amniocentesis where appropriate
• preimplantation genetic testing in selected circumstances
• implications for other family members

How is the test performed?

The test requires a blood sample collected into a Green Top Vacutainer.

Testing is performed on chromosomes from blood cells. Because chromosome analysis requires specialist laboratory processing and interpretation, results take longer than many routine blood tests.

Sample: Blood – Green Top Vacutainer
Reporting time: Approximately 4 weeks

What happens after the result?

If the result is normal, it means that no major chromosome rearrangement has been identified on standard karyotype analysis.

If an abnormality is identified, the significance depends on the specific chromosome finding. Some rearrangements have relatively small implications, while others may substantially alter the risk of miscarriage or an affected pregnancy.

We can discuss the result in the context of your pregnancy history and, where appropriate, arrange or recommend specialist genetic counselling and further testing.

Parental chromosome testing and recurrent miscarriage

Chromosome abnormalities in the pregnancy itself are a common cause of miscarriage. However, only a minority of couples with recurrent pregnancy loss have an underlying parental chromosome rearrangement.

For this reason, parental karyotyping is usually most useful when it is targeted to the clinical history, rather than performed automatically in every case.

For a broader overview of miscarriage investigations, causes and treatment options, see our guide to Understanding Recurrent Miscarriage.

Book parental chromosome testing

This product is priced per person. Where testing of both partners is clinically appropriate, each person requires a separate test.

If you are unsure whether this is the right investigation for you, consider booking a Specialist Miscarriage Consultation before proceeding.