Color of the amniotic fluid

Amniotic fluid consists of 99% water, in addition there are scoured fetal cells and organic components such as proteins, carbohydrates and fats, as well as electrolytes and urea. The color of the amniotic fluid, as well as the quantity, depends on the week of pregnancy. At the beginning of pregnancy, the amniotic fluid is usually clear or slightly milky.

At birth, the cheese smear colors the amniotic fluid yellowish-cloudy, so-called “Vernix flakes” become visible. Thus, the coloration of the amniotic fluid indicates the child’s readiness for birth. In addition, the amniotic fluid can take on other colors, which can indicate pathological changes.

Yellow amniotic fluid is found in cases of blood group incompatibility, whereby the blood group of mother and child do not match. This leads to an increased breakdown of red blood cells (erythrocytes), whose breakdown products (bilirubin) provide the characteristic yellow coloration. A flesh-colored coloration of the amniotic fluid is also possible and can indicate the death of the child in the womb. A greenish discoloration of the amniotic fluid is present when the child has already defecated (meconium) in the uterus. This happens especially when the child is under stress in the womb, as may be the case if the child is not supplied with enough oxygen.

Green amniotic fluid

The amniotic fluid is produced by the amniotic cavity itself and is completely renewed approximately every three hours. Normally, the amniotic fluid is clear and slightly yellowish in color. If the amniotic fluid is green, this usually indicates that the baby has already stopped having its first bowel movements in the womb, which is also known as child pitch (meconium).

This is not uncommon, and around 15% of live-born children are born in amniotic fluid containing meconium. For a large proportion, however, the first bowel movements are excreted in the first days of life after birth. The cause of premature stool removal (meconium) can be a stress situation of the child in the womb, such as lack of oxygen (hypoxia).

The danger of premature defecation in the womb is that amniotic fluid mixed with meconium can enter the baby’s lungs before or during birth, which can then result in a so-called meconium respiratory syndrome in about 5-10% of cases. Amniotic fluid with a green discoloration indicates meconium aspiration especially if the newborn is flaccid, the skin is bluish instead of rosy and breathing is greatly reduced. If this is not the case, meconium aspiration is unlikely and can be easily ruled out by the doctor.