What happens to the amniotic sac if there is no baby?

If there is no baby present, the amniotic sac may still form but will typically not develop normally. In cases of anembryonic pregnancy or blighted ovum, the sac can grow, but without an embryo, it may eventually collapse or be reabsorbed by the body. If the pregnancy is not viable, the body will usually recognize this and may lead to a miscarriage, resulting in the expulsion of the sac and associated tissues.