These data in most cases are detected by transvaginal ultrasound. As a rule, transabdominal ultrasound is less sensitive at such early stages of pregnancy.
Thus, to rule out an ectopic pregnancy, you may be advised to have your first ultrasound as early as 5 weeks (approximately a week of delayed menstruation). At this time, the fetal egg is already visualized in the uterine cavity, and at the same time it is not yet large enough to cause a rupture of the fallopian tube in the case of a tubal pregnancy.
If the first early ultrasound is done to make sure that the pregnancy is developing, then it is better to wait at least 6-7 obstetric weeks of pregnancy. Ultrasound at an early stage will also help answer such an important question as whether this pregnancy is singleton or multiple, as well as to distinguish between monochorionic and dichorial pregnancies.
Another important point will be the recommendation for the first or repeated ultrasound in the first trimester of pregnancy (obstetric period 8-9 weeks). The fact is that most stops in the development of pregnancy occur in the period before this period. A normally developing pregnancy at 8-9 weeks is clearly visible with a transabdominal sensor. At this time, the embryo begins to make the first movements and can already wave its arm or leg. If everything is normal at this stage, then the next ultrasound is recommended as early as 12-13 weeks in order to screen the first trimester of pregnancy.