40 days pregnant can do B-ultrasound examination?

Generally in women pregnant 40 days, do B ultrasound can see the gestational sac, and can rule out ectopic pregnancy. Do B ultrasound examination, radiation is small, will not affect the fetus, so you can rest assured that check. Note that before doing B ultrasound examination, be sure to hold urine, so that you can better observe the fetal situation.