If the HCG doubling is good, the possibility of ectopic pregnancy cannot be completely ruled out. If the pregnancy is ectopic, the pregnancy mass can be seen, there is a heart tube pulsation and the blood HCG doubling is also very good. You cannot determine whether the pregnancy is intrauterine or ectopic simply by the doubling of the blood HCG value, and the diagnosis should be further clarified in combination with pelvic ultrasound examination. If the time of conception is relatively short, it is possible that the ultrasound examination may not be able to detect the basis of pregnancy, and dynamic observation is necessary. In general, the fetal heartbeat and fetal bud can be detected around 6-7 weeks of pregnancy. If the ultrasound indicates that the pregnancy mass can be seen outside the uterus and there is a heart tube pulsation, it is more likely to be considered an ectopic pregnancy and hospitalization is recommended for timely treatment. If the ultrasound indicates an intrauterine gestational sac with fetal heart and fetal bud, the diagnosis of early intrauterine pregnancy can be made clearly, and the embryo is developing well.