PGD and PGT (embryo genetic testing) in Turkey

PGD, preimplantation genetic diagnosis, now usually called PGT, preimplantation genetic testing, is the testing of embryos created by IVF before one is transferred. A few cells are removed from each embryo at the blastocyst stage, the embryos are frozen, the cells are analysed, and an embryo shown not to carry the condition in question is transferred in a later cycle. It exists in three forms: testing for a specific inherited disease a couple carries, testing for a known chromosome rearrangement in one partner, and screening of all embryos for the wrong number of chromosomes, called PGT-A.

In Turkey, embryo testing is permitted for medical indications and carried out in licensed centres. Choosing the sex of the baby is not permitted, except to avoid a serious disease linked to sex, and a clinic advertising sex selection or family balancing in Turkey is advertising something it cannot legally do. The other honest point concerns PGT-A, the screening version sold to couples with no inherited disease: it has not been shown to increase the chance of a baby from a cycle, and it can discard embryos that would have become children.

The randomised trials of PGT-A, pooled in a Cochrane review, do not show that it increases the cumulative live birth rate from one egg collection, and the professional societies in Europe and North America do not recommend it routinely for all patients. Some trials suggest a higher live birth per transfer and fewer miscarriages in women over a certain age, which is the case for discussing it with a specific history rather than buying it as standard.

The reason is the biopsy and the biology. The cells removed come from the part of the embryo that becomes the placenta, not the baby; mosaicism means those cells can be abnormal while the baby would not be; and embryos reported abnormal are usually discarded. A screening test that discards some good embryos and cannot make bad ones good does not add babies. It changes the order and the count.

• No embryo to transfer. All embryos may be affected, abnormal or fail to reach blastocyst. The likelier the fewer embryos you produce.
• Discarding embryos that would have been fine. Mosaicism and test limits mean some embryos labelled abnormal could have produced a healthy child. Ask about mosaic policy.
• Biopsy damage. Small in experienced hands, not zero. Embryos can be damaged by removal of cells and by freezing and thawing.
• Misdiagnosis. Rare with PGT-M, but real, which is why prenatal confirmation is advised.
• No result. Some biopsies fail to give a result and the embryo is either re-biopsied, used untested or discarded.
• The risks of the IVF cycle. Hyperstimulation, procedure risks, multiple pregnancy if more than one embryo is transferred, ectopic pregnancy and miscarriage.
• Time, cost and two trips. Freeze-all, weeks of waiting and a second visit for transfer are built in, not optional.

• Check the centre's licence and the laboratory's accreditation. The genetic analysis may be done in-house or sent to a partner laboratory; ask which and how it is accredited.
• Ask who provides genetic counselling. A clinical geneticist or genetic counsellor, before and after, not a coordinator.
• Ask about test design for PGT-M. How your mutation is confirmed, how the test is validated, and how long that takes before the cycle.
• Ask the mosaic policy. Transferred with counselling, stored, or discarded. Centres differ and it changes your outcome.
• Ask about the second trip and storage. How long embryos are stored, what it costs, and how the frozen transfer is planned around your travel.
• Plan prenatal confirmation at home. For PGT-M, testing during pregnancy is still advised; agree who arranges it.

• European Society of Human Reproduction and Embryology, good practice recommendations for preimplantation genetic testing.
• Cochrane Library, preimplantation genetic testing for aneuploidies in in vitro fertilisation, systematic review.
• American Society for Reproductive Medicine, committee opinion on the use of preimplantation genetic testing for aneuploidy.
• Human Fertilisation and Embryology Authority, patient information on pre-implantation genetic testing and its add-on rating.
• Republic of Türkiye Ministry of Health, regulation on assisted reproductive treatment practices and centres.