Who needs PGT-SR?

PGT-SR is relevant where one partner carries a structural chromosome rearrangement — most commonly a balanced translocation, either reciprocal or Robertsonian, or an inversion. How people usually find out: investigation after recurrent pregnancy loss, or occasionally after a pregnancy or child with an unbalanced chromosome result. Carriers are healthy and generally have no other indication. ASRM (2026) recommends parental karyotyping be offered where chromosome testing of a miscarriage shows an unbalanced structural rearrangement, or where no chromosome testing of miscarriages is available — rather than testing every couple with recurrent loss routinely. The first step is now testing the miscarriage tissue itself. If a rearrangement is found, PGT-SR is one option. It is not the only one, and it should not be presented as the default. ASRM states the efficiency of PGT-SR versus expectant management has not been established. Observational studies report live birth rates as high as 70 to 71% in translocation carriers without any assisted reproduction. Practical considerations if you are weighing it: A balanced translocation substantially reduces transferable embryos — one study found an average of at least 4.5 blastocysts was needed for a good chance of one, with euploidy rates of 17 to 22% depending on maternal age. With advancing age or reduced ovarian reserve, several retrieval cycles may be needed, and IVF may not yield a transferable embryo at all. Ask for genetic counselling covering all routes, including natural conception with prenatal diagnosis and donor gametes.