Gestational sac development process

Pregnancy is a complicated process, starting from the initial combination of sperm and egg, to the ten months of gestation, and finally to the birth of healthy babies. The development of the fetus begins with the initial small embryo, when the fetus has not yet formed, and with the appearance of the embryonic bud, the fetal heartbeat begins to appear. After that, there are different changes every day. The gestational sac can be seen by B-ultrasound at 5 weeks of pregnancy. The fetus grows fastest in the second trimester and the baby can be born at 10 months of pregnancy.

1. How long does it take to see the gestational sac during pregnancy?

1. The gestational sac is the initial form of pregnancy. It is a small embryo wrapped in the original placental tissue by the amniotic membrane and vascular network. The fetus had not yet formed at that time, but the fetal heartbeat was already there when the embryo bud appeared.

2. The gestational sac is very small at the beginning and then grows slowly. 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.

3. 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.

2. How is the gestational sac formed?

The gestational sac is the primitive placental tissue, a small embryo wrapped by the amniotic membrane and vascular network. The gestational sac is the initial form of pregnancy. At that time, the fetus has not yet formed, and the fetal heartbeat is already there when the embryonic bud appears. In the second week, the embryo implants in the endometrium. When it develops into the second germ layer, a large cavity called the primary yolk sac appears on the ventral side of the embryonic disc. The yolk sac continues to shrink and degenerate during embryonic development, but the extraembryonic mesoderm on the wall of the yolk sac is the earliest origin of the formation of blood cells, blood vessels and primitive germ cells - the gestational sac, where the fetus will grow in the future.

3. The shape of the gestational sac determines the gender of the baby

Many netizens mentioned that the shape of the gestational sac can determine the gender of the baby, and an elongated shape may result in a boy. In fact, the shape of the gestational sac is determined by its tension and the space it can expand. If the mother's uterus has a relatively standard shape, the gestational sac will be round or oval in shape after implantation. If the mother's uterus is not standard or there are fibroids in the uterus, the shape of the gestational sac will change after implantation.

The difference in shape of the gestational sac of expectant mothers has nothing to do with the gender of the fetus. Generally, a well-developed gestational sac is round and flat, but sometimes the gestational sac will become longer with the shape of the uterine cavity. The shape of the gestational sac is determined by its tension and the amount of amniotic fluid it contains, and it will change its shape on its own. In this way, the gestational sac you see may be different depending on the number of days of pregnancy. In addition, the direction of the B-ultrasound probe is different each time, and the shape of the gestational sac is different when viewed from different angles.

Therefore, it is really a stretch to associate the shape of the gestational sac with the gender of the baby. It is not reliable to predict the gender of the baby based on the shape of the gestational sac.