A blood test for early pregnancy checks the HCG, or chorionic gonadotropin, in the blood, and if the report form is above the normal range, it indicates pregnancy. If the pregnancy is normal, the doubling will usually occur within 48 hours. If the doubling is not good in early pregnancy, it may be a badly developed embryo or an ectopic pregnancy, so if you have abdominal pain or vaginal bleeding, you should go to the hospital for a review in time. Normally, the gestational sac can be seen during an ultrasound around 40 days after menopause. If the gestational sac is not visible at this time and the chorionic gonadotropin in the blood is not doubling well, you should be highly alert to the possibility of ectopic pregnancy.