20 to 30 percent of IVF pregnancies result in multiple births. The hormone progesterone is given after egg retrieval until a pregnancy test is negative or sometimes throughout the first trimester. After the embryos have been transplanted, the woman may need to take it easy for a few days, or she may need to stay in bed for several hours to a few days. A blood pregnancy test will be taken 10 to 12 days after the embryos have been transplanted. If blood tests come back positive for pregnancy, a pregnancy ultrasound is scheduled to visualize the fetus and confirm a healthy heartbeat.