PGT (pre-implantation genetic testing)

The forms of PGT, and the old names

The UK fertility regulator, the HFEA, describes PGT-M, “previously known as preimplantation genetic diagnosis” (PGD), as a treatment that “involves checking the genes or chromosomes of your embryos for a specific genetic condition.”

It describes PGT-SR as “a treatment that involves looking at the chromosome structure of your embryos, and finding where segments may have been deleted, duplicated or inverted.”

And it says “PGT-A (previously known as preimplantation genetic screening or PGS) involves checking embryos for abnormalities in the number of chromosomes.”

What it involves

Every form needs IVF: “Because the embryos need to be tested in a lab, you will need to have IVF, even if you and your partner have no fertility problems.” The test itself is a biopsy: “To perform PGT-A, embryologists remove a cell, or if at a later stage, several cells (a biopsy), from the embryo, which are then tested to assess the number of chromosomes they contain.” The HFEA says “PGT-A is now mostly carried out at the blastocyst stage on day five or six.” See blastocyst culture.

What the regulator says about PGT-A

The HFEA lists PGT-A as a treatment add-on and publishes its own rating of the evidence. It explains why: “PGT-A is a selection tool that often reduces the number of embryos available for transfer.” It also notes “Sometimes, the result is reported as mosaic, which means the embryo contains both euploids and aneuploid cells.” Whether it is appropriate in a particular case is a clinical decision for the treating doctor. This directory does not make that judgement.

India’s ART (Regulation) Rules, 2022 set out two levels of clinic:

• A Level 1 clinic is one where “only IUI is carried out as part of treatment”.
• A Level 2 clinic is one where “all/advanced investigations, diagnostic and therapeutic procedures in ART are carried out”.

Because a Level 1 clinic may carry out only IUI, PGT is Level 2 work.

That is why each clinic below shows the level the national registry records for it. Of the listings below, 87 are registered as Level 2, 13 as Level 1, and 52 have no level in the registry extract. This directory does not know why a Level 1 clinic names PGT. A clinic may send patients to a partner Level 2 laboratory, or its website may describe services it does not provide on site. Ask the clinic where the PGT itself is done, and check its registration on the National ART & Surrogacy Registry.

What India's ART Act says

This is where Indian law is specific. Section 25(1) of the ART Act: “The Pre-implantation Genetic testing shall be used to screen the human embryo for known, pre-existing, heritable or genetic diseases only.”

The Act defines PGD as “the genetic diagnosis when one or both genetic parents has a known genetic abnormality and testing is performed on an embryo to determine if it also carries a genetic abnormality”. Section 26(1) adds that “the clinic shall not offer to provide a couple or woman with a child of a pre-determined sex.” Ask any clinic that offers PGT-A how its testing fits within section 25(1).