How long does it take to see the gestational sac during pregnancy

If normal intrauterine pregnancy, then 40 days of pregnancy, you can see the gestational sac in the uterus through B ultrasound, but because of individual differences, there are differences in the time of conception. Some pregnant women will delay about 45 days to see, if 49 days of pregnancy do not see the gestational sac, this may be ectopic pregnancy.