It is not recommended to take Ambien during pregnancy. The active drug in Ambien is considered a category C drug by the Federal Drug Administration. This means that studies have been conducted on animals resulting in side effects to the mother’s unborn fetus, such as decreased weight in the babies. There have not been enough studies conducted on humans as there are many risks associated with this. For mothers that have taken Ambien during the end of their pregnancy, infants experienced difficulty breathing after birth. If a lack of sleep is being experienced during pregnancy, it is best a physician is consulted to address the issue.