It is important to exercise safely (possibly under supervision by an instructor) during pregnancy, especially if you are considering a new type of exercise. Due to the online nature of these workouts, it is not advisable to join while pregnant. Some of the floor work is done reclining on your back and ladies in their second and third trimesters should not be in this position. It would be better to find a local class with an experienced instructor who can monitor you while exercising, to be safe.
It is advisable to wait at least 3 months postpartum before starting a new fitness regime. Special care must be taken regarding the type of exercise you do, especially the type and intensity of abdominal exercises, due to the changes in the abdominal wall and pelvis. Sometimes during pregnancy there is a separation of the Linea Alba (the central line between the Rectus Abdominis muscles) causing a condition called diastasis recti.
So you MUST see your GP BEFORE starting a new activity in the 3 months after childbirth.