In vitro fertilization (IVF) success rates are lower in older women, and embryos obtained with IVF in older women are more likely to be chromosomally abnormal. When donor eggs from younger women are used, the age-related differences in IVF success disappear. Perhaps if the chromosomally normal embryos of older women could be identified and selected for transfer during an IVF cycle, IVF success would be higher in these patients. This is the rationale of preimplantation genetic screening (PGS), and it makes perfect sense. This technique has become aggressively marketed in the IVF community as a way to boost IVF success rates in older women. However, in my own program, we don’t offer it, mainly because it hasn’t been proven effective to my satisfaction.
In a recent study performed in the Netherlands, more than 400 infertile women 35 through 41 years of age who were scheduled for IVF were randomly assigned to having IVF with or without PGS, for up to three cycles. It turned out that the continuing pregnancy rate was lower in the group who got PGS. This is the second study of its type to show such results. Why isn’t PGS helping?
Maybe the people who did the embryo biopsies weren’t very skilled, or perhaps the ovarian stimulation protocols didn’t yield enough embryos to make a difference. One of the randomized studies has been criticized because two cells were removed from each embryo. However, it is likely that the benefit of PGS is overcome by the damage that occurs when performing the embryo biopsy. Also, some people think that the chromosome count of a single cell is not representative of the rest of embryo; that is, there may be a high degree of mosaicism in preimplantation embryos, and the embryos identified as abnormal by PGS could actually result in normal infants
In any case, I think it is the responsibility of IVF programs that perform PGS to better document the benefit of this procedure before they make patients (or their insurance companies) pay for it.
MPS
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You said it, Dr S.
I underwent IVF with ICSI at age 35 after trying for my first pregnancy for 2 years. My husband had a slightly abnormal SA that may be from his previous exposure to chemotherapy (you can comment on that if you'd like). They wanted me to have PGD since I was 35. No thanks, I said. Especially since they were charging $4000 out of pocket.... I knew my chances for an abnormality based on our history and I also trusted nature to take care of any abnormalities they could have picked up with PGD, accepting the consequences if nature didnt....
I got pregnant the first attempt and have a wonderful son after a very traumatic pregnancy (threatened miscarriage, chronic abruption, fetal abnormalities). The genetic testing on my son is all completely normal, however, he does have a syndrome, there is just no test for it....
Are there any abnormalities or genetic syndromes related to IVF with ICSI, or with chemo exposure to the dad?
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