A couple has had three first-trimester miscarriages. Which single investigation assesses parental chromosomal causes?

Answer: B. Karyotyping of both partners

Parental karyotyping in recurrent miscarriage

Parental chromosomal abnormalities are an important cause of recurrent pregnancy loss.

Investigation

• Karyotyping of both partners is done when investigating recurrent miscarriage (two or more losses), subfertility, intrauterine death, or the birth of a child with anomalies.

What it detects

• A balanced translocation carrier (about 1 in 500 people) is phenotypically normal, but their pregnancies carry a high risk of unbalanced chromosomes, which mainly cause miscarriage (and rarely a child with anomalies).
• Products of conception can also be karyotyped.

Management

• Refer for genetic counselling; options include IVF with pre-implantation genetic testing.

So karyotyping of both partners assesses parental chromosomal causes.