Occasionally, pregnancies produce either too little or too much amniotic fluid, which is the fluid that surrounds the baby. What results is a set of possible risks or complications known as oligohydramnios (OH-lee-go-hy-DRAM-nee-os) and polyhydramnios (pol-ee-hy-DRAM-nee-os).
Amniotic fluid cushions the baby from outside stresses and gives the baby enough room to move and grow inside the womb. It also keeps some space between the baby, the umbilical cord, and the uterine wall, so that the cord doesn’t become compressed.
Because the amniotic fluid typically reflects the amount of urine the fetus is producing, it’s used as a measure of the baby’s health and development. If the amount of fluid is low, it may be an indication that:
- Your water is breaking
- The baby has intrauterine growth restriction (IUGR)
- The baby is having kidney or urinary tract problems
- The baby has a rare genetic disorder
- The placenta is separating from the uterine wall prematurely (placental abruption)
- The mother has chronic high blood pressure or is using certain medications, such as ACE inhibitors
In rare cases, an amnioinfusion could be performed to increase the amount of amniotic fluid, but it hasn’t been shown to be effective in the long-term. This procedure involves filling the amniotic sac with saline using a needle inserted through the mother’s abdominal wall. The extra fluid may help relieve some problems, such as lifting pressure off a kinked umbilical cord, or it may enhance an ultrasound image so that the doctor can diagnose the underlying problem.
Polyhydramnios occurs when there is an excessive accumulation of fluid. Polyhydramnios has many different causes, and therefore treatments can widely vary.
Most cases of polyhydramnios are mild. Amniotic fluid may have gradually built up during the later stages of pregnancy. Normally, it won’t cause any problems and will go away on its own.
Severe polyhydramnios, however, may cause outward symptoms, such as shortness of breath, swelling in the feet, ankles, and vulva, and decreased urine production.
Causes of Polyhydramnios
- Rh incompatibility (mother and baby’s blood types are incompatible)
- Fetal anemia (low red blood cell count in the fetus)
- Maternal diabetes
- Genetic conditions
- Complications due to multiple gestation
If left untreated, severe polyhydramnios may increase the chances of complications, such as macrosomia, preterm labor and birth, and placental abruption. The earlier the problem starts, the more time it has to build up excessive fluid, which increases the chances of complication.
Fortunately, your OB-GYN should be able to catch polyhydramnios with a routine ultrasound. If we suspect polyhydramnios, we may need to perform further tests to diagnose the precise cause of the condition.
Treatments for Polyhydramnios
Usually, treating polyhydramnios is as simple as treating the underlying problem causing it. For example, if we determine that the excess fluid is caused by maternal diabetes, then successfully treating the mother’s diabetes should resolve the polyhydramnios.
However, your doctor may recommend treatment that directly targets the build-up of fluid.
Draining the surplus amniotic fluid
Your OB-GYN may perform an amniocentesis in order to relieve the uterus of excess fluid. Sometimes more than one amniocentesis is required; this process is called amnioreduction.
The oral medication Indocin can cut down on the baby’s urine production, which will decrease the amount of amniotic fluid. However, this drug is not recommended for use after 31 weeks of pregnancy, and carries some risk for fetal heart problems. The baby’s heart will need to be carefully monitored with a Doppler ultrasound or an echocardiogram.
Your doctor will continue to measure your amniotic fluid every 1-3 weeks. Usually, pregnancies with mild and moderate polyhydramnios will be able to be carried to full term. However, in serious cases of polyhydramnios, labor may be induced early to avoid complications.