The theory behind this procedure is that removing all but a few eggs maintains the possibility of pregnancy while reducing the risk of multiple births and ovarian hyperstimulation. Although data on this procedure are preliminary, selective follicular reduction may offer a financially acceptable alternative to those who cannot afford IVF while avoiding moral dilemma associated selective fetal reduction. IVF can be both a cause and a solution to the problem of multiple births associated with fertility treatment. Implanting multiple embryos has more than doubled the number of triplets, quadruplets and quintuplets in the United States, producing 81 sets of quintuplets and 560 sets of quadruplets between 1989 and 1996. In most of Europe regulations prevent physicians from transferring more than two or three pre-embryos into a woman's uterus, but there are no similar regulations in the United States.
Physicians often implant four or five embryos.
Some doctors insert as many as 10 in hopes of boosting the achieving a pregnancy. While IVF was initially found to be a major factor in the increased numbers of high order multiple births, that is not case today. Indeed, IVF may be our best solution to the risk of multiple births. Recent studies indicate that success rates in younger women vary little with increasing number of embryos transferred, while the risk of multiple births increases dramatically. At this stage the embryos are heartier and have a much higher implantation rate, thus necessitating the transfer of fewer embryos.