Oligohydramnios

What is an Oligohydramnios

Oligohydramnios is too little amniotic fluid, defined quantitatively as a single deepest vertical fluid pocket depth less than 2 cm or total AFI of less than 8 cm.

A lack of amniotic fluid can impair fetal lung development and result in fetal pulmonary hypoplasia with high fetal morbidity and mortality.

Oligohydramnios can result from a variety of etiologies including

fetal d emise,

fetal r enal abnormalities, 

i ntrauterine growth retardation (IUGR), 

p remature rupture of membranes, 

p ost dates, and 

c hromosomal abnormalities (mnemonic DRIPPC).

Oligohydramnios is a condition in which there is not enough fluid in the sac (amniotic sac) that surrounds your unborn baby (fetus). The amniotic sac in the uterus contains fluid (amniotic fluid) that:

• Protects your baby from injury (trauma) and infections.
• Helps your baby move freely inside the uterus.
• Helps your baby’s lungs, kidneys, and digestive system to develop.

This condition occurs before birth (is a prenatal condition), and it can interfere with your baby’s normal prenatal growth and development.

Oligohydramnios can happen any time during pregnancy, and it most commonly occurs during the last 3 months (third trimester). It is most likely to cause serious complications when it occurs early in pregnancy. Some possible complications of this condition include:

• Early (premature) birth.
• Birth defects.
• Limited (restricted) fetal growth.
• Decreased oxygen flow to the fetus due to pressure on the umbilical cord.
• Pregnancy loss (miscarriage).
• Stillbirth.

What are the causes?

This condition may be caused by:

• A leak or tear in the amniotic sac.
• A problem with the organ that nourishes the baby in the uterus (placenta), such as failure of the placenta to provide enough blood, fluid, and nutrients to the baby.
• Having identical twins who share the same placenta.
• A fetal birth defect. This is usually an abnormality in the fetal kidneys or urinary tract.
• A pregnancy that goes past the due date.
• A condition that the mother has, such as:
  • A lack of fluids in the body (dehydration).
  • High blood pressure.
  • Diabetes.
  • Reactions to certain medicines, such as ibuprofen or blood pressure medicines (ACE inhibitors).
  • Systemic lupus.

In some cases, the cause is unknown.

What increases the risk?

This condition is more likely to develop if you:

• Become dehydrated.
• Have high blood pressure.
• Take NSAIDs or ACE inhibitors.
• Have diabetes or lupus.
• Have poor prenatal care.

What are the symptoms?

In most cases, there are no symptoms of oligohydramnios. If you do have symptoms, they may include:

• Fluid leaking from the vagina.
• Having a uterus that is smaller than normal.
• Feeling less movement of your baby in your uterus.

How is this diagnosed?

This condition may be diagnosed by measuring the amount of amniotic fluid in your amniotic sac using the amniotic fluid index (AFI). The AFI is a prenatal ultrasound test that uses painless, harmless sound waves to create an image of your uterus and your baby. An AFI prenatal ultrasound test may be done:

• To measure the amniotic fluid level.
• To check your baby’s kidneys and your baby’s growth.
• To evaluate the placenta.

You may also have other tests to find the cause of oligohydramnios.

How is this treated?

Treatment for this condition depends on how low your amniotic fluid level is, how far along you are in your pregnancy, and your overall health. Treatment may include:

• Having your health care provider monitor your condition more closely than usual. You may have more frequent appointments and more AFI ultrasound measurements.
• Increasing the amount of fluid in your body. This may be done by having you drink more fluids, or by giving you fluids through an IV tube that is inserted into one of your veins.
• Injecting fluid into your amniotic sac during delivery (amnioinfusion).
• Having your baby delivered early, if you are close to your due date.

Follow these instructions at home:

Lifestyle

• Do not drink alcohol. No safe level of alcohol consumption during pregnancy has been determined.
• Do not use any tobacco products, such as cigarettes, chewing tobacco, and e-cigarettes. If you need help quitting, ask your health care provider.
• Do not use any illegal drugs. These can harm your developing baby or cause a miscarriage.

General instructions

• Take over-the-counter and prescription medicines only as told by your health care provider.
• Follow instructions from your health care provider about physical activity and rest. Your health care provider may recommend that you stay in bed (be on bed rest).
• Follow instructions from your health care provider about eating or drinking restrictions.
• Eat healthy foods.
• Drink enough fluids to keep your urine clear or pale yellow.
• Keep all prenatal care appointments with your health care provider. This is important.

Contact a health care provider if:

• You notice that your baby seems to be moving less than usual.

Get help right away if:

• You have fluid leaking from your vagina.
• You start to have labor pains (contractions). This may feel like a sense of tightening in your lower abdomen.
• You have a fever.