OLIGOHYDRAMNIOS (LOW AMNIOTIC FLUID) Part 1

Amniotic fluid is a protective water-like fluid that surrounds the fetus (baby) in the uterus (womb) throughout pregnancy and is contained within a casing called the amniotic membrane or sac.  It is an essential component of pregnancy and fetal development.  Amniotic fluid is mostly water in the early stages of pregnancy. However, as the pregnancy progresses, the amniotic fluid changes composition and serves new functions.

The fetus begins to inhale and swallow amniotic fluid, which aids in the development of the lungs and digestive system. When amniotic fluid is swallowed, it is digested by the developing gastrointestinal system of the fetus, and the byproducts are excreted in the fetal urine on a regular basis. The amniotic fluid contains less water and more fetal urine around week 20 of gestational age.

Amniotic fluid that women normally carry ranges in volume from 500 to 1000 ml. The level may change depending on the mother, fetal weight, and gestational stage. However, throughout the pregnancy, the amount of amniotic fluid should remain above a set minimum. It guards against infection, prevents umbilical cord compression, helps the fetus develop its muscles and limbs, and cushions their movements while inside the uterus. It also maintains the fetus’s temperature.

However, too little (Oligohydramnios) or too much amniotic fluid (Polyhydramnios) in the uterus is linked to abnormalities in foetal development and may lead to pregnancy complications.

While there are two types of amniotic fluid disorders, “Oligohydramnios” will be the subject of our attention for today.

WHAT IS OLIGOHYDRAMNIOS?

Oligohydramnios is a pregnancy condition where there is insufficient amniotic fluid surrounding the fetus.  According to research, about 4% of pregnant women experience low amniotic fluid. In the last three months of pregnancy, when it is most prevalent. Because amniotic fluid levels start to decline after 40 weeks of pregnancy, this rate increases to about 12% in those who are past their due date.

Low amniotic fluid (Oligohydramnios)  may indicate an underlying condition or contribute to fetal health issues. These conditions may impair a baby’s growth or causes complication during labor and delivery.

CAUSES OF OLIGOHYDRAMNIOS

Oligohydramnios may be caused by numerous factors. It is typically brought on by conditions that hinder or reduce the production of amniotic fluid.

The following are some factors associated to oligohydramnios:

• Placental Abnormalities: When the placenta is unable to supply the fetus with enough blood and nutrients, the fetus stops recycling fluid, which may result in a decrease in the amount of amniotic fluid.
• Leaking or Rupture of Fetal Membranes: This may be a gush of fluid or a slow constant trickle of fluid in the fetal membranes due to tear or uterine rupture which may result to low amniotic fluid levels.
• Maternal Health Condition: A crucial component of the amniotic fluid is maternal water. Low amniotic fluid may be caused by the mother’s health.

Dehydration, or a lack of water, may lead to nutritional deficiencies and poor tissue perfusion, which may be harmful to the developing fetus and the pregnant woman’s health.

Preeclampsia, also known as maternal hypertension, is a hypertensive condition that develops during pregnancy. Due to the placenta’s and fetus’s constrained blood supply, these conditions lead to a reduction in placental perfusion. This could cause the fetus to receive less oxygen and nutrients, which could lead to oligohydramnios.

Maternal diabetes is a condition in which the kidneys may have to work extra hard to filter and absorb the extra glucose that accumulates in the blood. Dehydration may result from the excess glucose and bodily fluids that are excreted in the urine when the kidneys are unable to keep up.

• Birth defects: Low levels of amniotic fluid may be caused by congenital anomalies that may have an impact on the fetus’s kidney or urinary tract development and cause little urine production.
• Post Term Pregnancy: Low levels of amniotic fluid may occur in post-term (pregnancies lasting over 42 weeks), which may be caused by deteriorating placental function.
• Twin-to-Twin Transfusion Syndrome: Identical twins and higher-order multiples who share a placenta may develop this serious disorder. This happens when the placentas of the babies are connected at the blood vessels. Due to this, one baby (this twin is called the recipient) receives more blood flow, whereas the other baby (this twin is called the donor) receives insufficient blood flow. In this state of transfusion, the donor twin has less blood volume, which slows down the development and growth, as well as less urinary output, which results in a lower level of amniotic fluid than normal.

SIGNS AND SYMPTOMS OF OLIGOHYDRAMNIOS

The following are common signs and symptoms of oligohydramnios. However, each woman may have a unique set of symptoms which may include:

• Amniotic fluid leakage when the cause is an amniotic sac rupture
• Decreased amount of amniotic fluid  than expected on ultrasound scan
• Measurement of the uterus is smaller than expected for the gestational age
• Smaller abdomen size for the gestational age
• Slow heartbeat of the fetus
• The clinician can easily feel the fetus when abdomen of the mother is touched
• Less frequent fetal movements than usual
• Lower maternal weight than normal for the gestational age …………………………………………….………TO BE CONTINUED