How often do assisted reproductive technology treatments produce multiple children?
Assisted reproductive technologies, especially the way they are practiced in the United States, have a high association of multiple gestation and the reason for this, of course, is because the doctors that practice IVF, or practice assisted reproductive technologies, are as motivated as the patients to try to make the procedure be successful, so they try to tip the balance in their favour by transferring multiple embryos. If one embryo has a 20% chance of implanting, then two embryos will have will have a higher chance of implanting, and so on. It's like rolling multiple dice in an effort to get at least one of them to come up with the number six. However, if you roll four dice, every once in a while, those dice will all come up with sixes and then you'll have a multiple gestation. So, in the United States the multiple gestation rate is about 37%. It's quite high. More than one third of all pregnancies in the United States from assisted reproduction are multiple gestations. In contrast, in Europe or in other parts of the world where infertility is covered by insurance, the insurance company commonly mandates that no more than one embryo may be replaced. Well, if you only put back one embryo, then you can really only have one baby, unless of course that one embryo splits into identical twins, but that's very rare. The reason we have multiple gestations with assisted reproduction is because we're putting back multiple embryos. So, if you only put back one embryo, really, you should only have one baby, and the incidence of multiple gestation in Europe and other places in the world where infertility is covered by insurance is much lower, and really approaches what it would be in nature, which is about one percent.
