Polyhydramnios is a pregnancy condition during which there is excess amniotic fluid. Polyhydramnios is the opposite of oligohydraminos, during which there is an amniotic fluid deficiency. Amniotic fluid is liquid contained inside a mother’s amniotic sac. The amniotic fluid protects and surrounds the fetus inside the uterus. Amniotic fluid also aids development of the fetus’s lungs, muscles, limbs, and digestive system. Polyhydramnios can cause complications with fetal growth and development.
Causes of Polyhydramnios
Often, the cause of polyhydramnios cannot be directly identified. Furthermore, a case of polyhydramnios can have multiple causes. During the first stages of pregnancy, the majority of the amniotic fluid is comprised of water made by the mother. After approximately 20 weeks, the primary element is urine from the fetus. Polyhydramnios is often caused by conditions that cause the fetus to produce excess urine.
Causes of polyhydramnios can include:
- Multiple pregnancies
- Rh incompatibility
- Intrauterine infection
- Gastrointestinal abnormalities
- Maternal kidney or cardiac conditions
- Maternal diabetes causing frequent fetal urination
- Neurological abnormalities, including anencephaly
- Annular pancreas due to malformation in pancreas development
- Chromosomal abnormalities, including Down’s syndrome and Edwards syndrome
- Fetal renal disorders that result in increased urine production, such as antenatal Bartter syndrome
- Esophageal or duodenal astresia, or abnormal closing or absence of the esophagus or duodenum
- Twin-twin transfusion syndrome, during which one twin receives excess blood flow and the other receives a shortage
Failure to Diagnose Polyhydramnios
Polyhydramnios should be investigated immediately if a patient exhibits certain clinical signs. In most cases, polyhydramnios is easily treated with no serious complications if closely monitored. However, harm can occur if a medical professional fails to properly diagnose and treat symptoms of polyhydramnios. One of the main symptoms of polyhydramnios is an abdominal or uterine size that is disproportionate to the mother’s weight gain and gestational age.
Other clinical signs for polyhydramnios include:
- Chest heaviness
- Shiny skin that exhibits stria
- Dyspnea, or shortness of breath
- Faint fetal heart sounds during examination
Polyhydramnios can result in:
- Preterm labor
- Cesarean delivery
- Premature rupture of the membranes
- Intrauterine growth restriction, which can cause skeletal malformations
- Placental abruption, or separation of the placenta and the uterine lining
- Postpartum hemorrhage
Diagnosis and Treatment
There are tests used to measure polyhydramnios and associated amniotic fluid levels. One of the most common testing uses amniotic fluid index (AFI). If an amniotic fluid index shows more than 25 centimeters of fluid, it can be diagnosed as polyhydramnios. Deep pocket measurements can also detect polyhydramnios. A fluid level of 2000 milliliters or more can indicate polyhydramnios.
Monitoring of polyhydramnios includes sonograms to measure fetal growth. Fetal assessments and biological profiles are also taken. If polyhydramnios occurs before 32 weeks gestation, medications can be administered to reduce fluid production. Amnioreduction can also be performed to drain excess fluid content.This process uses amniocentesis. If the fetus has reached adequate development, delivery is also recommended.