Amniotic fluid is crucial for the healthy development of the fetus. However, having too little or too much of this fluid in the uterus can lead to various complications.
What is amniotic fluid?
In the uterus, the baby is located inside the amniotic sac, which consists of two membranes: the amnion and the chorion. The fetus grows and develops inside this sac filled with amniotic fluid.
Initially, the fluid is produced by the mother, and by the 20th week of pregnancy, by the fetal kidneys, as the fetus swallows and excretes the fluid.
What does amniotic fluid look like?
Amniotic fluid is clear or pale yellow. If the fluid changes color, it may mean that your baby has passed meconium (the baby's first stool) in the womb. (In this case, the fluid usually looks green or brown). If the fluid changes color, the doctor will check whether the baby has any breathing problems.
Functions of amniotic fluid
The functions of amniotic fluid are as follows:
- Protecting the fetus: acts as a shock absorber, protecting the baby from external pressure;
- Temperature regulation: helps maintain a normal body temperature inside the womb;
- Protection against infection: because amniotic fluid contains antibodies, it protects the baby from various infections;
- Development of the lungs and digestive system: as the baby breathes in the fluid, its lungs and digestive system develop;
- Muscle and bone development: while floating inside the amniotic sac, the baby moves freely and without restriction, allowing the muscles and bones to develop properly;
- Amniotic fluid prevents fingers and toes from fusing together; if amniotic fluid levels are low, the fingers and toes may grow fused together;
- Protecting the umbilical cord: fluid in the uterus reduces the risk of the umbilical cord being compressed. Through it, nutrients and oxygen pass from the placenta to the fetus.
Typically, amniotic fluid levels increase up to the 36th week of pregnancy, reaching approximately 1 liter, and then decrease as birth approaches.
Fluid abnormalities
Sometimes, there may be more or less amniotic fluid than usual. Oligohydramnios is when the level of amniotic fluid is lower than normal.
Oligohydramnios can occur in any trimester, but it most often occurs in the last trimester. If it appears in the first 6 months of pregnancy, the risk of birth defects, miscarriage, or preterm birth is high.
If fluid levels are low in the last trimester, it can lead to the following:
- Slowed fetal growth;
- Difficulties during labor;
- The need for delivery by cesarean section.
The remainder of the pregnancy is also monitored to ensure that the baby is developing normally.
Polyhydramnios (sometimes also called hydramnios or an amniotic fluid disorder) is the presence of more fluid than normal.
Mild cases of polyhydramnios usually do not require special treatment. In severe cases, where there is an excessive buildup of fluid, amniocentesis is performed (the excess fluid is drawn off with a needle). Anti-inflammatory drugs such as indomethacin are no longer recommended just to reduce the fluid, because they can harm the baby. From the 20th week of pregnancy, do not take such drugs unless your doctor tells you to.
If you notice amniotic fluid leaking during pregnancy (especially before 37 weeks, or if the fluid is green, brown, bloody or foul-smelling), contact your doctor or the maternity hospital immediately. Any pregnant woman who is worried that she has too little or too much fluid should also tell her doctor.
