How long does it take for the yolk sac to be visible?

The yolk sac is the key substance connecting the test tube embryo and the pregnant mother. Therefore, the most important issue for pregnant mothers during pregnancy is the time when their yolk sac appears. Only when the yolk sac appears can the fetal heartbeat appear and the fetus can grow and develop normally. But some pregnant mothers delay the appearance of yolk sac during pregnancy, so when is the latest time for yolk sac to appear?

How long does it take for the yolk sac to be visible?

During pregnancy, the yolk sac will gradually begin to appear around 5 weeks of pregnancy. 1-2 weeks after the yolk sac appears, the fetal heartbeat and fetal bud will begin to appear. Some pregnant women have not found the existence of yolk sac when they went for B-ultrasound after 5 weeks of pregnancy. Pregnant mothers do not need to worry at first. When your menstruation is delayed or ovulation is delayed, these situations may cause the yolk sac to appear too late. But generally speaking, the latest time for the yolk sac to appear is around 8 weeks of pregnancy. If the yolk sac has not appeared after this period of time, you need to go to the hospital for examination, find out the cause of the disease, and treat it in time.

After the yolk sac appears, it will expand with the expansion of the uterus. When it reaches 8 to 12 weeks of pregnancy, the yolk sac begins to shrink and gradually disappear. The time when the yolk sac appears will be different due to the different physical conditions of each pregnant woman, but if the examination results are normal, pregnant mothers do not need to worry too much.

What causes a small yolk sac?

A small yolk sac is a manifestation of yolk sac atrophy. If the yolk sac atrophies, it will immediately lead to the occurrence of fetal arrest. There are many reasons for the small yolk sac, the most important of which is caused by emotional anxiety. Mental anxiety causes delayed menstruation and pregnancy time is later than the actual time, so the actual size of the yolk sac is smaller than the number of days of amenorrhea. The problem of a small yolk sac caused by this is not very serious. As long as the yolk sac continues to grow and the fetal heartbeat and fetal heartbeat appear, pregnancy can be continued.

Another reason for the small yolk sac is that due to the incomplete development of sperm and egg, the yolk sac will also be incompletely developed. Although the yolk sac will grow with the increase of pregnancy time, if the fetal heartbeat and fetal heartbeat cannot be seen for a long time, this kind of yolk sac is unhealthy and will eventually cause miscarriage in pregnant women.