At the beginning of pregnancy, a fertilized egg enters the uterine cavity, is attached to the wall and an embryo develops. At the same time, it is surrounded by a fetal egg and attached to a yolk sac. In the first 3-4 weeks after conception, the embryo is so small that it can not be visualized. The first study is conducted at 6-7 weeks, when the uzi can be seen embryo, pregnancy . Earlier this period it is rather problematic to visualize it.
From 4 weeks the embryo is not clearly visualized, but an experienced physician will be able to determine its presence or absence in the fetal egg by characteristic features:
- darkening in the center of the fetal egg;
- black dot in the fetal egg;
- the unevenness of the contents of the egg against the background of its uniform and even shells.
Pregnancy without an embryo is usually called anembryonia. In this case, the fetal egg is, the level of hCG in the blood of the pregnant woman is increasing, but the embryo is not liable, i.e. the ultrasound doctor does not see anything in the cavity of the fetal egg.
Accurate and reliable data on what week the embryo is being visualized, at the moment, no. There is a time frame in which there is a high probability of its detection. But this period varies from 3 to 9 weeks, and depends on many factors:
- individual features of the female body;
- accuracy of calculations for the period of ultrasound;
- Multiplicity of pregnancy (for the first pregnancy is characterized by a small embryo, which then rapidly develops, and therefore is visualized later).
However, the average statistical norm is visualization of the embryo by the seventh week of pregnancy, in parallel with the intensive growth of hCG. Direct dependence on the level of hCG and the visibility of the embryo is not, however, stopping the growth or falling levels of hCG is a sign of a frozen pregnancy , with or without a visualized fetus. The future mother should be worried only if the embryo is not visualized at the 7 week time period against a background of stopping the growth or fall of the hCG level. But even in this situation, it is recommended to undergo another study by another specialist, or to resort to transvaginal ultrasound, since it has greater accuracy and informativeness.
In the event that 1-2 weeks after stopping hCG growth, the embryo is not visualized even with transvaginal ultrasound - and the time is nearing 9 weeks, the future mother should listen to her body. If the embryo has stopped its growth, it can
- unmotivated temperature increase;
- nausea, vomiting;
- weakness, pain in the muscles;
- bloody discharge from the vagina (from red to brown);
- lower abdominal pain.
These symptoms are accompanied by the decomposition of the embryo and the earlier fading of pregnancy, which requires diagnostic scraping to prevent serious consequences for the health of women.