According to Dr.Amitha Indersen, Consultant Fetal Medicine specialist-Apollo Cradle Jubilee Hills, Amniotic fluid is the wonder liquid in which new life takes form, grows and develops. The term amniotic fluid is derived from the Latin words ‘liquor amnii’.
Amniotic fluid serves multiple functions. Early in gestation, the fetus floats in the fluid which allows for free movement and in turn, the formation of joints and movements. The fluid is breathed in and out by the fetus and this helps the lungs to grow and air sacs to develop. When the fetus swallows the fluid. It passes through the intestinal tract. This, besides helping the intestines to for and function, the debris present in it helps form the meconium or the first stool that the new born passes. One of the most important functions is to act as a cushion and protect the fetus from mechanical forces.
In early pregnancy, the amniotic fluid is primarily secreted by the mother’s womb and the membranes. As the fetus grows beyond 14 weeks gestation, the secretion of fluid is taken over by the fetus. When the fetus passes urine, breathes in and out and the fluid that passes through the immature skin all contribute to the amniotic fluid. Later in pregnancy, most of the fluid is derived from the fetal urine.
The level of fluid in the womb has been an indicator for fetal wellbeing. When the fluid is less , it is called Oligohydramnios and when it is in excess, it is called polyhydramnios. Polyhydramnios can be due to various causes. The most common of these are maternal diabetes affecting pregnancy, block in the fetal respiratory or gastro intestinal tract, fetal anaemia, any mass in the fetal chest, movement disorders, anything interfering with normal fetal swallowing and structural defects that cause fluid to ooze out. Not all of these can be detected before birth. Problems like lower intestinal obstruction, trachea oesophageal fistula, certain skin and movement disorders are difficult to diagnose before birth.
Oligohydramnios also has multiple causes. When there is a problem in placental function or fetal growth restriction, the blood flow to the fetal kidneys are reduced and in turn , fetal urine production is reduced. In some women, there maybe a leak of the fluid resulting in problems. When the fetal kidneys are not formed or the function is affected due to various causes, the fluid levels can diminish.
So the amniotic fluid provides a warm cushioned environment for the fetus to move about in, grow and develop. Any reduction or excess of fluid can be indicative of an underlying problem and needs evaluation and follow up.