What are the reactions to insufficient amniotic fluid?

If there is insufficient amniotic fluid, pregnant women will often have some reactions. It is also very detrimental to the development of the fetus, and can easily lead to respiratory distress or even more serious situations. When there is insufficient amniotic fluid, pregnant women can easily feel fetal movements, which may cause pain. The fetus will suffer from hypoxia, which can often induce fetal malformations and other adverse conditions.

What are the reactions to insufficient amniotic fluid?

Pregnant women often feel pain due to fetal movement. The abdominal circumference and the height of the uterine fundus are smaller than the gestational month. The fetal movement is restricted and it is difficult to rotate naturally, so breech presentation is more common. The pregnancy time is prolonged, often exceeding the expected date of delivery by 2 to 3 weeks. During delivery, primary uterine atony or uncoordinated uterine contractions often occur, the cervix dilates slowly, and the first stage of labor is prone to prolongation. The amniotic fluid is very small, viscous, and mostly yellow-green, which can cause fetal hypoxia.

Various developmental malformations are caused by lack of amniotic fluid. For example, if too little amniotic fluid occurs in early pregnancy, part of the fetal body surface may adhere to the amniotic membrane, or form amniotic bands, causing fingers or limbs to be severed. If oligohydramnios occurs in late pregnancy, the fetus's skin will be dry and parchment-like. Due to the low amniotic fluid, the fetus is in a forced position in the uterus and is easily compressed, causing special musculoskeletal deformities, such as hand and foot deformities, dorsiflexion, torticollis, and bending of the upper and lower limbs.

There is also often poor fetal lung development, which may be caused by:

① Developmental defects in the lungs, which prevent the excretion of fluid to maintain the amount of amniotic fluid.

② Due to the low amount of amniotic fluid, the uterus presses on the fetal chest, affecting the expansion of the chest wall and lungs.

③ Lack of fluid inhalation into the terminal alveoli hinders lung development. In normal pregnancy, the intake of an adequate amount of amniotic fluid is important for the expansion and development of the fetal lungs. Oligohydramnios that occurs in early and mid-pregnancy often ends in miscarriage due to fetal malformation.

Causes of oligohydramnios

1. Fetal malformation

Many congenital malformations, especially urinary system malformations, are related to oligohydramnios, such as congenital renal agenesis, renal dysplasia, polycystic kidney disease, and urethral stenosis or atresia. The above-mentioned deformities lead to reduced or no urine production, and the urine produced cannot be excreted or the excretion is reduced, resulting in anuria or oliguria, which leads to a decrease in amniotic fluid production, normal amniotic fluid absorption, and finally oligohydramnios.

2. Placental insufficiency

The placenta is the organ for the exchange of substances between the fetus and the mother. Reduced placental function can lead to a decrease in fetal blood volume, a decrease in fetal renal blood supply, and ultimately a decrease in fetal urine production.

3. Drug effects

Many drugs can cause oligohydramnios, the most common of which are non-steroidal antipyretic analgesics and angiotensin-converting enzyme inhibitors.

This article introduces in detail some of the physical manifestations of pregnant women with oligohydramnios, and also explains what exactly is causing oligohydramnios. As a pregnant woman, you must carefully observe your physical condition. Once you find symptoms of oligohydramnios, you need to take immediate measures to correct them, otherwise big problems may arise.