What is the Difference Between Polyhydramnios and Oligohydramnios

The key difference between polyhydramnios and oligohydramnios is that polyhydramnios is the excessive production of amniotic fluid during pregnancy, while oligohydramnios is the inadequate production of amniotic fluid during pregnancy.

Polyhydramnios and oligohydramnios are two pregnancy-related complications. Both conditions are due to the changes in the volume of amniotic fluid. Amniotic fluid is very important as it cushions the baby from outside stress and gives the baby enough space to move and grow in the womb. It also keeps space between the baby, umbilical cord, and uterine wall. This will prevent the umbilical cord from compressing. However, too much production or too little amniotic fluid leads to complications.

CONTENTS

1. Overview and Key Difference
2. What is Polyhydramnios
3. What is Oligohydramnios
4. Similarities – Polyhydramnios and Oligohydramnios
5. Polyhydramnios vs Oligohydramnios in Tabular Form
6. Summary – Polyhydramnios vs Oligohydramnios

What is Polyhydramnios?

Polyhydramnios is the excessive production of amniotic fluid during pregnancy. In this condition, amniotic fluid accumulates excessively and surrounds the baby in the uterus during pregnancy. Polyhydramnios occurs in 1 or 2% of pregnancies. It results in exertion pressure within the uterus and nearby organs. The signs and symptoms of polyhydramnios are shortness of breath, swelling in the lower extremities and the abdominal wall, uterine discomfort, and fetal malposition (breech presentation).

The causes of polyhydramnios include a birth defect that affects the baby’s gastrointestinal tract or nervous system, maternal diabetes, twin-twin transfusion, fetal anemia, blood incompatibilities between mother and baby, and infection during the pregnancy. The complications involved in this condition include premature birth, premature rupture of membranes, placental abruption, prolapsed umbilical cord, C-section delivery, stillbirth, and heavy bleeding.

Moreover, polyhydramnios can be diagnosed through ultrasound, blood test, amniocentesis, nonstress test, and biophysical profile. Furthermore, treatment options for polyhydramnios may include treating underlying conditions like maternal diabetes, drainage of excess amniotic fluid, and medication (oral medication called indomethacin that helps to reduce fetal urine production and amniotic fluid volume).

What is Oligohydramnios?

Oligohydramnios is a condition involving an inadequate amount of amniotic fluid during pregnancy. It affects 4% of people who are pregnant. Oligohydramnios is more common in the last three months of pregnancy. The causes of oligohydramnios include congenital anomalies that affect the baby’s kidneys or urinary tract, problems in the placenta, going past the due date (more than two weeks), hypertension, diabetes, dehydration, prelabour rupture, and twin-twin transfusion syndrome. The signs and symptoms of this condition may include an amniotic fluid index of 5cm or less, fluid leaking from the vagina, an abnormally smaller uterus, not feeling the movement of the baby, and a decrease in the baby’s movements. The complications include deformities caused by being compressed in the uterus, preterm birth, miscarriage, stillbirth, infection, fetal growth restrictions, respiratory issues, and increased risk of cesarean delivery.

Moreover, oligohydramnios can be diagnosed through ultrasound, amniotic fluid index (AFI), or maximum vertical pocket (PPV). Furthermore, oligohydramnios can be treated through fluid replacement through maternal oral or IV hydration and amnioinfusion.

What are the Similarities Between Polyhydramnios and Oligohydramnios?

• Polyhydramnios and oligohydramnios are two pregnancy-related complications.
• Both conditions are due to changes in the volume of amniotic fluid.
• Both conditions can cause complications.
• They can be diagnosed through ultrasound.
• They can be treated through drainage or infusion of amniotic fluid.

What is the Difference Between Polyhydramnios and Oligohydramnios?

Polyhydramnios is the excessive production of amniotic fluid during pregnancy, while oligohydramnios is the inadequate amount of amniotic fluid during pregnancy. Thus, this is the key difference between polyhydramnios and oligohydramnios. Furthermore, polyhydramnios affects 1 to 2% of people who are pregnant, while oligohydramnios affects 4 % of people who are pregnant.

The below infographic presents the differences between polyhydramnios and oligohydramnios in tabular form for side-by-side comparison.

Summary – Polyhydramnios vs Oligohydramnios

Polyhydramnios and oligohydramnios are two pregnancy-related complications. Both these conditions are due to the changes in the volume of amniotic fluid. Both these conditions may cause complications as well. Polyhydramnios refers to the excessive production of amniotic fluid during pregnancy. In contrast, oligohydramnios refers to having an inadequate amount of amniotic fluid during pregnancy. So, this is the key difference between polyhydramnios and oligohydramnios.

Reference:

1. “Polyhydramnios.” NHS Choices, NHS.
2. “Oligohydramnios: Etiology, diagnosis, and management in singleton gestations.” UpToDate.

Image Courtesy:

1. “Tweeling transfusiesyndroom” By Leiden Fetal Therapy – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “Ultrasound Scan ND 152505 1531230 cr” By Nevit Dilmen (talk) – Own work (CC BY-SA 3.0) via Commons Wikimedia