Reproductive genetics: when testing changes the plan, and when it does not

Reproductive genetics is the set of tools that brings DNA into the fertility consultation: preconception carrier screening, prenatal screening and diagnosis, preimplantation genetic testing on embryos, and tests of the endometrium itself. Used well, these change plans and prevent suffering. Used routinely, they add cost and complexity without changing outcomes.

The four broad categories

Preconception genetic counseling looks at the parents – family history, ethnicity, prior pregnancies. It tries to identify risk before conception. Prenatal genetic screening and diagnosis happens during pregnancy: NIPT, nuchal translucency, anatomy scan, sometimes chorionic villus sampling or amniocentesis. Preimplantation genetic testing (PGT) looks at embryos created in IVF before transfer – chromosomes, single-gene disorders, or chromosomal rearrangements. Endometrial Receptivity Array (ERA) tests the lining of the uterus, not the embryo, to fine-tune transfer timing.

What genetic testing changes

For families with known inherited conditions, PGT-M can prevent transmission. For couples with recurrent pregnancy loss linked to chromosomal causes, PGT-A may improve per-transfer success. For carrier couples discovered through preconception screening, the conversation about donor gametes or PGT-M is shaped by what was found. These are real, evidence-based uses.

What it does not change, despite marketing

Routine PGT-A in fertile couples under 35 with normal embryos has not been shown to improve cumulative live-birth rates in the most rigorous trials. The same procedure adds biopsy risk to every embryo and reduces the number of embryos eligible for transfer. ERA was once promoted as universally beneficial; current evidence suggests it helps a subset of patients with repeated implantation failure, not everyone.

How to decide

Ask: what specifically would change in our plan based on the test result? If the answer is concrete (we would transfer a different embryo, we would consider donor gametes, we would change transfer timing by 12 hours), the test is probably worth its cost. If the answer is “we would feel more reassured,” that is real value too, but it is not a clinical indication.

Questions worth asking your doctor

• Which of these tests are you recommending for us specifically, and what would change in our plan based on each result?
• What is the evidence base for the test in patients like us – not all patients?
• What is the cost, and what does that cost include or exclude (the biopsy itself, the lab, the per-embryo charge)?
• What are the risks – to embryos, to me, to interpretation of borderline results?

This essay is educational. Every patient’s situation is different – the right plan is shaped in conversation with a fertility specialist who knows the full picture.