A drop in HCG during early pregnancy is not promising if laboratory error or human error is ruled out as the cause. If there is a drop in HCG it should be retested in case of laboratory error or human error. The HCG needs to be increasing during early pregnancy, increasing by 1.7-2.0 times every other day. HCG represents the quality of the embryo and whether the pregnancy is normal or not. If there is an abnormal increase in HCG, or if there is a decrease instead of an increase, it means that the quality of the embryo is not good or there is a possibility of ectopic pregnancy. Therefore, it is important to check the ultrasound when the HCG decreases to rule out ectopic pregnancy first, and then to see if there is a fetal bud or fetal heartbeat in the reverse fertility.