Is having a yolk sac good news?

It is said that our life is hard-earned, and this is indeed the case. Before every fetus is born, any unexpected things will happen, especially in the early stages of pregnancy. Pregnant women must pay special attention to body care, pay attention to more rest, adjust their diet, keep a happy mood, etc. When doing a prenatal check-up, if the doctor finds a yolk sac, then it is good news.

Is having a yolk sac good news?

The presence of a yolk sac indicates that the embryo can develop. The yolk sac is the predecessor of the embryo bud, so the yolk sac will grow first and then the embryo bud. The yolk sac is inside the gestational sac. It is to provide hormonal support to the embryo, not food for the gestational sac. If you see a gestational sac in the uterus and a yolk sac inside the sac, it can be confirmed as an intrauterine pregnancy. Generally, fetal heartbeat can be seen around 45 days after pregnancy, and sometimes a little earlier. This is only according to the rules of the menstrual cycle. If the cycle is long, it should be postponed.

When does the yolk sac appear?

Under normal circumstances, the condition should be visible about 7 weeks after menopause. Pay attention to local hygiene and strengthen nutrition. The diameter of a normal yolk sac is between 3 and 10 mm, and it usually disappears in 8 to 10 weeks. If you are pregnant, you need to have an ultrasound examination to determine the development of the embryo. Generally speaking, the gestational sac and yolk sac can be detected on the 35th day of pregnancy. If the menstruation is delayed, ovulation may be delayed, and the appearance of the yolk sac, embryo and fetal heart will also be delayed accordingly.

Yolk sac formation

A membrane sac rich in blood vessels located on the ventral side of the embryo and surrounding the yolk. The contracted part that communicates with the embryo's midgut is called the yolk sac stalk. The cyst wall is composed of an inner layer of extraembryonic endoderm and an outer layer of extraembryonic mesoderm. During a normal human pregnancy, the size of the yolk sac increases with the gestational age from 5 to 11 weeks, and shrinks until it disappears after 12 weeks of pregnancy. The occurrence of human embryo yolk sac is also one of the phenomena of (law of system recapitulation) recapitulation system occurrence.

The extraembryonic mesoderm on the human yolk sac forms many blood islands in the third week. It is the first site where blood vessels and blood cells are formed in the embryo. It is the hematopoietic site of the early embryo (before 10 weeks). The yolk sac artery and vein will participate in the formation of the mesenteric artery and portal vein. Since primordial germ cells first appear in the yolk sac wall, the yolk sac is the original origin of germ cells. Yolk sacs are also found in other vertebrates and in the cephalopod mollusks.

The mature follicle forms a corpus luteum after ovulation. During the angiogenesis period, blood flows into the corpus luteum cavity (corpus luteum hematoma), so under normal conditions, the corpus luteum is cystic. Under pathological conditions, if its diameter is 1.5--2.5cm, it is called a cystic corpus luteum; if it exceeds 2.5cm, it is called a corpus luteum cyst.