How big is the gestational sac during pregnancy

For pregnant mothers, the happiest thing is to witness the baby in their belly grow day by day. However, since the baby is still in the form of a gestational sac in the early stages of pregnancy, pregnant women will not experience many symptoms. However, when you go to the hospital for B-ultrasound, you can also detect the size of the gestational sac, which directly reflects the health of the baby. So how big is the gestational sac of a two-month-old pregnant woman?

How big is the gestational sac when pregnant for two months

First Month

1 Fetal growth

About 7-10 days after fertilization, the fertilized egg implants in the endometrium, absorbs nutrients from the mother, and begins to develop. During the first 8 weeks, it should be called an embryo, not a fetus.

The size of the embryo in the late third week of pregnancy is about 0.5-1.0 cm long and weighs less than 1 gram, but its shape can be seen with the naked eye. Externally, the embryo cannot clearly distinguish between the head and body, and has gill arches and a tail, which is no different from the embryonic development of other animals.

Second month of pregnancy

1 Fetal growth

At 7 weeks of pregnancy, the fetus is about 2.5 cm long and weighs about 4 grams. The heart, stomach, intestines, liver and other internal organs and the brain begin to differentiate. Organs such as hands, feet, eyes, mouth and ears have been formed. It can be said that it is getting closer and closer to the human form, but it is still small in body and big in head.

The chorion becomes more developed, the placenta is formed, the umbilical cord appears, and the connection between mother and fetus is very close.

Three months of pregnancy

1 Fetal growth

At this point, when this period ends, the embryo can officially be called a fetus. The fetus is about 7.5-9 cm long and weighs about 20 grams.

The tail has completely disappeared, the shapes of organs such as the eyes, nose, mouth, and ears are clearly discernible, and the fingers of the hands and feet are also clearly visible, almost exactly the same as those of ordinary people.

The internal organs are more developed, the kidneys and genitals have grown, the urethra begins to form and excrete fluid begins to fill the fetus.

Four months pregnant

1 Fetal growth

At the end of the 15th week, the fetus is about 16 cm long and weighs about 120 grams.

At this time, the baby has a complete human appearance, and the difference in the genitals can be used to distinguish between males and females. The skin begins to grow fetal hair, the bones and muscles gradually develop, the hands and feet can make slight movements, the internal organs are basically complete, the heart beats actively, and the heart sounds can be measured with an ultrasonic stethoscope.

sound. The doctor can feel the fetal head and buttocks on the pregnant woman's abdominal wall to determine the position of the fetus in the uterine cavity.

What is a fetal sac

The gestational sac is actually the original placental tissue, which is a small embryo wrapped in the amniotic membrane and vascular network. The gestational sac is the initial form of pregnancy, when the fetus has not yet formed. The fetal heartbeat already begins when the embryo bud appears. The embryo implants into the endometrium in the second week and 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.

The gestational sac is only seen in early pregnancy. For women who have regular menstruation of 28 to 30 days, after 35 days of amenorrhea, the gestational sac can be seen in the uterine cavity by B-ultrasound. The diameter of the gestational sac is about 2 cm at 6 weeks of pregnancy and about 5 cm at 10 weeks of pregnancy. It is normal for the gestational sac to be located in the upper or middle part of the anterior and posterior walls of the fundus of the uterus; it is normal for the gestational sac to be round or oval and clear in shape; if the gestational sac is irregular and blurred and located in the lower part, and the pregnant woman also has abdominal pain or vaginal bleeding, she may have a miscarriage.