What is the cause of the early gestational sac?

In the early stages of pregnancy, women's gestational sacs are very small. As the months of pregnancy increase, women's bellies will become larger and larger. This is a normal phenomenon. In addition, in the early stages of pregnancy, because the fertilized egg is not particularly stable when implanted in the uterus, there may also be some fetal instability. So why is the gestational sac large in the early stages of pregnancy?

Their properties are the same. Before the fetus is formed, it is called a gestational sac, and after it is formed, it is called an embryo.

Generally, during embryonic development, a gestational sac is formed in 30-40 days, a fetal bud is formed in 40-50 days, and a fetal heartbeat is formed in 50-60 days. You have been amenorrhea for two months. If there is still no fetal heartbeat, it may be that development has stopped. Or if your menstruation is usually delayed, then late fertilization cannot be ruled out as the cause. You can check again after a week or so. If the same situation persists, then there is a high possibility of pregnancy arrest and you need to consider abortion. There are many reasons for this situation. Before the next pregnancy, both men and women should do a comprehensive pre-pregnancy check-up. If there is a problem, actively treat it to prevent and reduce the chance of recurrence.

Generally speaking, after 5 weeks of pregnancy, a small gestational sac can be seen on B-ultrasound, which occupies less than 1/4 of the uterine cavity, or a fetal bud can be seen. If it is a normal intrauterine pregnancy, the gestational sac can be seen in the uterus through B-ultrasound around 40 days of pregnancy. However, due to individual differences in the time of conception, some pregnant women may not be able to see it until around 45 days.

Usually, when HCG reaches 1000U/L, vaginal ultrasound should be able to identify the intrauterine gestational sac. This is around the 4th or 5th day of the 5th week of pregnancy. When HCG reaches 6500U/L, abdominal ultrasound can identify the intrauterine gestational sac. Therefore, vaginal ultrasound will be more accurate. If the intrauterine gestational sac is not seen on the 49th day of pregnancy during a normal menstrual cycle, ectopic pregnancy should be suspected.

3. How long does it take for the embryo to form during pregnancy? The embryonic period begins after 5 weeks of pregnancy.

Pregnancy is a complex process. After the egg is fertilized, it enters the uterine cavity, and the embryo and its appendages grow and develop rapidly until they mature. There will be different changes in each week of pregnancy.

4 weeks: The fetus is only 0.2 cm. The amniotic cavity is formed just after the fertilized egg has implanted and its volume is very small. Ultrasound cannot show clear signs of pregnancy.

5 weeks: The fetus grows to 0.4 cm and enters the embryonic period. The amniotic cavity expands and primitive cardiovascular system appears, which may beat. B-ultrasound can show a small gestational sac, which occupies less than 1/4 of the uterine cavity, or a fetal bud can be seen.

6 weeks: The fetus grows to 0.85 cm, and the head, brain alveoli, facial organs, respiratory, digestive, and nervous organs are differentiated. The fetal sac is clearly visible on B-ultrasound, and the fetal bud and fetal heartbeat are seen.

7 weeks: The fetus grows to 1.33 cm. The embryo has the rudiments of a human being. The body segments are fully differentiated, the limbs are separated, and various systems are further developed. B-ultrasound clearly shows the embryo and fetal heartbeat, and the gestational sac occupies about 1/3 of the uterine cavity.

8 weeks: The fetus grows to 1.66 cm. The fetal shape is determined, and the head, body and limbs can be distinguished. The head is larger than the trunk. B-ultrasound shows that the gestational sac occupies about 1/2 of the uterine cavity, the fetal shape and fetal movement are clearly visible, and the yolk sac can be seen.

9 weeks: The fetus grows to 2.15 cm, the head is larger than the body, the various parts are clearer, the skull begins to calcify, and the placenta begins to develop. B-ultrasound shows that the gestational sac almost fills the uterine cavity, the fetal outline is clearer, and the placenta begins to appear.

10 weeks: The fetus grows to 2.83 cm, all fetal organs have been formed, and the rudiments of the placenta are formed. B-ultrasound shows that the gestational sac begins to disappear, a crescent-shaped placenta is visible, and the fetus is active in the amniotic fluid.