Preimplantation genetic testing for aneuploidy (PGT-A) is widely used in IVF with the aim of improving embryo selection, reducing miscarriage and shortening time to pregnancy. Yet evidence supporting its routine use remains uncertain, particularly for the outcome that matters most to IVF patients: the cumulative chance of having a baby from an IVF cycle.

Most trials have focused on outcomes after the first embryo transfer of an IVF cycle, and PGT-A does appear to reduce miscarriage. However, there is concern that PGT-A could also reduce the overall chance of having a baby from IVF. Embryo biopsy may itself cause harm; false-positive results may lead to potentially viable embryos being discarded; and embryos classified as mosaic or inconclusive may not be transferred despite retaining reproductive potential. Earlier generations of aneuploidy screening provide an important cautionary example: screening performed using FISH analysis on day 3 embryos was introduced widely before adequate evaluation and was later shown to reduce live birth rates.

Patients may be told that PGT-A can identify the “best” embryo or reduce miscarriage without an equally clear explanation that evidence for its effect on cumulative live birth is limited, that some embryos may be excluded from transfer, and that uncertainty remains around mosaic results.

Newer approaches, including parental genotyping, may improve embryo classification and reduce unnecessary embryo exclusion, while non-invasive methods could reduce procedural harm. These advances are promising, but new technology should not bypass rigorous evaluation. Large randomised trials that assess cumulative live birth and other patient-important outcomes are urgently needed before newer forms of PGT-A are adopted widely.