The Highs and Lows of Amniotic Fluid
Just Floating Along
The sac of waters, or the amniotic sac, is vital to your baby's existence in the womb. It is his life support system and has several important functions.
· If you slip and fall, the amniotic fluid cushions the baby to protect him.
· It stops the umbilical cord from compressing, reducing the baby's oxygen and nutrient supply.
· It helps to keep the temperature in the womb constant.
· It protects the baby from infection.
· It provides an environment that allows for easy movement so the baby's muscles and bones develop properly.
· It helps the digestive system and the respiratory system to develop through the baby's swallowing and breathing the fluid in and out.
How Does the Fluid Form?
The amniotic sac is formed within two weeks of conception and the fluid comes in soon after. For the first weeks and months it is comprised of water and fluid from you, and then at about 20 weeks the primary substance in the sac is the baby's urine produced as the baby starts swallowing the fluid. It passes through his kidneys and is excreted as urine, which he swallows again - and so it goes.
The levels of amniotic fluid constantly increase until about 32 weeks gestation, then they level off. Sometimes the levels of fluid are too high and sometimes they are too low. Normal levels are considered to be an Amniotic Fluid Index (AFI) of 5 to 25 centimeters or a fluid level of about 800 to 1000ml. If the fluid measurements are below 5 centimeters, the condition is called oligohydramnios and if the measurement is above 25 centimeters, it is called polyhydramnios.
How Does Low Amniotic Fluid Affect My Baby?
While oligohydramnios (too little amniotic fluid) can happen at any point during a pregnancy, it is most common during the last trimester. Passing the due date for delivery by two weeks or more raises the risk of oligohydramnios. Once you reach 42 weeks gestation it is possible for the fluids to decrease by half at that point and beyond. Oligohydramnios can cause complications when a pregnancy goes past 41 weeks. Some of the risks associated with low amniotic fluid include:
· Birth defects as a result of compression of fetal organs
· Increased risk of stillbirth or miscarriage
· Intrauterine growth restriction
· Preterm birth
· Labor complications (cord compression, meconium stained fluid and cesarean delivery)
What Causes It?
Low amniotic fluid can be caused by a number of different things.
· Birth defects - if the baby has developmental problems of the kidneys or urinary tract that could affect urine production.
· Placental problems - not enough blood and nutrients getting to the baby could cause the baby to stop recycling fluid.
· Leaking or rupture of the membranes - whether a gush or a trickle, it can reduce the levels of fluid.
· Past due date - gestation past 42 weeks can affect fluid levels and cause slowing of placental function.
· Maternal complications - preeclampsia, diabetes, dehydration and high blood pressure in the mother can affect the amniotic fluid levels.
How is Oligohydramnios Treated?
Treatment for oligohydramnios is based upon the gestational age of the baby. If you are not full term, the doctor will closely monitor you and the levels of amniotic fluid. Non-stress tests and contraction stress tests may be ordered to determine how your baby is doing, checking his activity. If your pregnancy is close to full term, then the doctor may recommend delivering the baby, either by induction or cesarean delivery. There are other treatments for oligohydramnios that include:
· Amnio-infusion during labor. An intrauterine catheter is inserted into the uterus and a saline fluid is pumped in to help pad the umbilical cord during delivery - keeping it from compression and collapse and from hurting the baby. This also reduces the need for a cesarean delivery.
· An injection of fluid prior to delivery through amniocentesis.
· Re-hydrating the mother with intravenous or oral fluids to help increase amniotic fluid levels.
Low amniotic fluid levels can increase labor and delivery complications. If your baby is unable to tolerate labor, then a cesarean will be performed for his safety.