In vitro fertilization (IVF) is the process of introducing a fertilized egg into the uterus and allowing it to settle, so the doubling of HCG is generally normal, just as it would be in a normal pregnancy. In vitro fertilization is the process of growing a fertilized egg into a blastocyst in a test tube and then transferring the blastocyst into the uterine cavity where it can be implanted. As long as the blastocyst is successfully implanted, and as long as you follow the doctor’s instructions and take progesterone and other medications to preserve the pregnancy, then generally speaking, the blastocyst will successfully implant, and the doubling of the HCG will also be normal. Pregnant women should not be overly anxious about the possibility of a bad HCG doubling when undergoing IVF, as long as they are regular with their maternity checkups and consult their doctors for advice when they encounter abnormalities, they can achieve a relatively good pregnancy outcome.