<human>:  I have a question about in vitro fertilization. When a woman has a miscarriage, is it possible that the embryo was not viable?
<bot>: Yes, it is possible that the embryo was not viable. In vitro fertilization is a process that involves fertilizing an egg outside of the body, and then transferring the embryo to the uterus. If the embryo is not viable, it will not implant in the uterus and the pregnancy will end.