Illustration of ovarian stimulation in the form of a chart of the first hormonal menstrual cycle during IVF. The red strip represents the time period of the FSH (follicle-stimulating hormone) injection (from the 2nd to the 12th day), the pink strip, the injection of GnRH antagonist (from the 7th to the 12th day) and the green strip, the injection of HCG (human chorionic gonadotropin) on the 12th day. On the 13th day, the oocytes are retrieved for fertilization (IVF), then the embryos are transferred to the uterus on the 16th day (yellow cones). The blue strip represents the injection of progesterone from the 13th to the 29th day.