Mosaic embryos are similar to the healthy embryos that have always been used for in vitro fertilization (IVF), but mosaic embryos contain a mixture of both abnormal and normal cells. One can be successfully implanted in the uterine wall and develop into a healthy fetus. It can go on to be a fully formed, healthy baby.
Unfortunately, that is not always the case. Mosaic embryos have a greater risk of miscarriage. Infants may also have a greater chance of being born with birth defects. Scientists aren’t really sure how much of an increased risk there is, however. Plus, IVF has always been a difficult process with no guaranteed outcome.
Some say that the decision should be made by the potential parents. After all, we screen for Down syndrome and neural tube defects. Parents are given the option to terminate based on those findings. The problem is that as of right now, legislators and reproductive endocrinologists could make the decision to stop the transfer of mosaic embryos entirely. Whose decision should it be?
According to the National Post, “Richard Scott, founder and laboratory director at Reproductive Medicine Associates of New Jersey, told The New York Times in 2016, ‘Every research program is fearful of throwing away a healthy embryo, but on the other hand, mosaicism is not always a benign thing.’ He continued, ‘Now we are paying attention to these mosaics, but we don’t know exactly what to do with them.’ Several more mosaic embryo transfers have resulted in the birth of healthy babies in the two years following the article.”
Those concerned say that there is no way for prospective parents to fully understand the risks. Parents, though, are often called upon to make these types of decisions during pregnancy. The new testing to identify mosaic embryos has raised a much bigger question: “What level of genetic perfection is considered acceptable?”