Continuing the Conversation: Dr Nalini Mahajan on Women’s Fertility and IVF
Q) How does preimplantation genetic testing (PGT-A, PGT-M) affect IVF success rates? A) Preimplantation genetic testing—so now, there are two types, as you’ve written: PGT-A and PGT-M. PGT-A is for aneuploidies, which are numerical chromosomal abnormalities that happen with age. Normally, you have a certain number of chromosomes: 22 pairs plus either XX or XY. If there’s a break or error—for example, an extra chromosome—it’s called a trisomy. If there’s one missing, like XO, it’s a monosomy. These abnormalities often lead to miscarriages. Since age increases the risk of these aneuploidies, if an older woman is going for IVF, we do advise, if possible, to test the embryos for these abnormalities. If you find a normal embryo, it will give you a better chance at success. PGT-M is for monogenic diseases. If there’s an inherited disorder in the family—say, a BRCA mutation—you can test for that using PGT-M. But for this, you must know the exact mutation—which gene, which chromosome, and wha...