How many weeks of pregnancy does amniotic fluid appear

Generally, amniotic fluid will begin to appear around 8 to 10 weeks of pregnancy. At this time, the amniotic fluid is mainly composed of the mother's blood cells, which enter the amniotic cavity through the fetal membrane. After the second trimester, the fetus's urine becomes the main source of the amniotic fluid of the pregnant woman, which will gradually reduce the plasma osmotic pressure of the amniotic fluid of the pregnant woman. In the third trimester, the fetal lungs of the fetus will participate in the conversion of amniotic fluid of the pregnant woman. Generally, 600 to 800 ml of fluid are metabolized from the bronchus to the amniotic cavity every day. In addition, a small amount of fluid will exude from the amniotic membrane, Wharton's jelly, and the skin of the fetus and become the amniotic fluid of the pregnant woman.

Around 10 weeks of pregnancy, amniotic fluid begins to be produced. As the pregnancy progresses, the amount of amniotic fluid will increase. At 38 weeks of pregnancy, the amount of amniotic fluid reaches its peak, about 1000 ml. After that, the amniotic fluid of pregnant women will gradually decrease. Amniotic fluid less than 300ml is considered oligohydramnios. B-ultrasound shows that the depth of amniotic fluid is less than 3cm and the amniotic fluid index is less than 8cm. Malformed fetus, decreased placental function, amniotic membrane disease, pregnancy-induced hypertension and other diseases may often cause a decrease in amniotic fluid in pregnant women. The pregnant woman's amniotic fluid exceeds 2000ml. It indicates that there is too much amniotic fluid. B-ultrasound shows that the depth of amniotic fluid exceeds 8cm and the amniotic fluid index exceeds 18cm, which is greatly correlated with fetal malformation and placental dysfunction.

In most cases, women will begin to feel fetal movement after 16 weeks of pregnancy. However, because each fetus has different sizes in terms of mobility, and the thickness of pregnant women's abdominal fat is also different, and pregnant women themselves feel the fetal movement differently, so the time when they feel the fetal movement will vary. Some women may be able to feel obvious fetal movements around 16 to 18 weeks of pregnancy, while some women may not feel obvious fetal movements until around 21 to 22 weeks.

The number of weeks of pregnancy when fetal movement occurs depends on the development of the fetus, but generally women who are pregnant for the first time will feel fetal movement around 16-20 weeks of pregnancy, but the strength will be relatively small. After a woman's pregnancy is four months old, the fetal movements become more obvious from the fifth month, and the fetus is more active.