That she is intaking a sufficient amount of oxygen with adequate tidal volume so that her organs remain perfused. If she is not taking in sufficient oxygen she will goninto shock due to the lack of oxygen before seizing, going into Cardiac Arrest, and expiring.
You need to provide some form of supplementary oxygen if she does not have adequate tidal volume and her Spo2 has the potential to get worse so you'd automatically hook her up to oxygen via an NRB. If her respirations begin to fail you provide positive pressure ventilation via BVM.
The placenta is a flattened circular organ in the uterus of pregnant eutherian mammals, nourishing and maintaining the fetus through the umbilical cord.