The most commonly used methods to check for pregnancy are blood HCG and ultrasound, which is used to confirm whether or not pregnancy is intrauterine. If a woman has regular menstruation, it can in principle be seen by ultrasound if the menstrual period has stopped for more than 35 days from the first day of the last menstrual period. In the case of regular menstruation, a delay of one week or more can be used to find out if you are pregnant through a pregnancy test or blood HCG. After the pregnancy has been clarified it is still necessary to detect whether the pregnancy is intrauterine or extrauterine, which requires an ultrasound. Generally, the pregnancy sac can be seen by ultrasound at about 5 weeks after menopause, and without vaginal bleeding or stomach pain you can wait until about 6 weeks to see the fetal heart, buds and heartbeat. The time of appearance is not fixed, some late implantation or ordinary irregular menstruation of pregnant women, such as did not see the fetal buds or heartbeat can be one week after the recheck, but if the recheck and still do not see the heartbeat and the gestational sac did not increase significantly, may be considered to be embryonic failure. Therefore, 40 days pregnant, ultrasound is certainly visible, need to pay attention to whether it is in the uterus or ectopic, if it is ectopic pregnancy, need to be treated early, to avoid the later rupture triggered hemorrhage, resulting in irreversible serious consequences. Early on, you can perform a negative ultrasound, see more clearly, pay attention to rest, can not carry out strenuous exercise, do not have sex.