Why Does IVF Fail?
Much of Dr. Sills’ schedule is dedicated to helping patients with failed IVF cycles from elsewhere. Initially, the first thing that needs to happen is to obtain all the outside records for review (and this may require several weeks). Using your records as a starting point for review, here are common questions Dr. Sills likes to frame as a new treatment plan is developed for you at CAG:
- Could follicular recruitment be optimized to increase oocyte yield?
- Do any underlying metabolic issues exist which may impact egg quality?
- Have intrauterine contours been adequately evaluated?
- Which agent was used to trigger ovulation, and when was it given?
- Did the embryo transfer proceed normally?
- What type (and dose) of supplementary progesterone was used?
- Are there roles for additional testing of sperm and endometrium?
Sometimes there will be more than one issue requiring correction going forward. For example, the gonadotropin stimulation protocol and ovarian response will form a crucial part of our review. But so will sperm quality and fertilization effectiveness. Certainly anatomic factors, immunological factors, and imbalances in the blood clotting/clot dissolving system can also adversely affect embryo implantation. Yet, the most critical parameter that impacts the IVF success rate tends to be the competency of the oocyte (egg). Put another way, the age of the ovary is the single biggest factor influencing reproductive outcomes with IVF.
Recently, Dr. Sills was invited to present his data on embryo genetics at the annual meeting (2015) of the Pacific Coast Reproductive Society. His lecture was notable because it was the first to focus on the rate of genetic error in embryos that were derived from anonymous donor eggs. These donors were all under age 30, were non-smokers, and some already had pregnancies of their own which did not require fertility medications. So these women should have made the BEST embryos, since they were expected to produce the BEST oocytes.
However, Dr. Sills and his team reported something genuinely unexpected. Even among the embryos which should have been of the very best quality, guess what the rate of chromosomal error was? Only 46.8% were chromosomally normal. In other words, MANY embryos can be genetically abnormal even when the age of the ovaries is very low (as with egg donor IVF cycles).
From this, one can infer that an important driver of IVF failure relates to embryo genetic error. Abnormal embryos are more likely to undergo developmental arrest and fail to implant. Genetic problems in the embryo cannot be reliably detected by grading or scoring of embryos, which rely on the physical appearance (“morphology”) of the embryo when photographed before transfer. Accordingly, specific testing—at the molecular level—for chromosomal competency in embryos before embryo transfer can help identify those embryos that are best suited for transfer—thereby lifting pregnancy rates with IVF.