Vaginal ultrasounds are usually required 2-3 times after embryo transfer. After the embryo transfer, a follow-up visit to the Fertility Center is required 12-14 days later for a blood pregnancy test to check for blood HCG (human chorionic gonadotropin). If you are already pregnant, you will need to continue treatment with luteal support medication and regular ultrasounds. An ultrasound should be done 35 to 40 days after conception to see the pregnancy sac. Also rule out ectopic pregnancy. An ultrasound should be done between forty-five and fifty days after conception to look at the fetal heart. Ultrasound should be done between eleven and thirteen + six weeks of pregnancy to check the thickness of the fetal nuchal translucency, to observe the presence of abnormal fetal development and to provide a basis for prenatal examination. The gestational week for IVF is mainly estimated based on the time of transfer. During the post embryo transfer checkup, the reproductive medicine doctor will correct the last menstrual period based on the time of transfer.