Polyhydramnios is a condition in which there is too much amniotic fluid produced during pregnancy. Initially, amniotic fluid originates from maternal blood that diffuses across the placenta. This fluid is later swallowed by the developing fetus and the volume of the amniotic fluid increases as the fetus urinates. Amniotic fluid acts as an important cushion for the fetus and also provides temperature regulation while aiding in lung and kidney development. As the fetus gets closer to term, s/he will produce between 500 and 1200 ml of urine each day and swallow between 210 to 760 ml of amniotic fluid each day. Any disruption in this balance can drastically increase (or decrease) the amount of amniotic fluid in the womb.
Reinforce what you read in this article by tuning in to learn about polyhydramnios in episode 244 of the Straight A Nursing podcast. Listen from any podcast platform, or straight from the website here.
What causes polyhydramnios?
Some possible etiologies of polyhydramnios include:
- Uncontrolled maternal diabetes – The elevated blood glucose levels lead to polyuria in the fetus, which increases the amount of amniotic fluid.
- Esophageal atresia or duodenal atresia in the fetus – In these conditions, the fetus is not able to swallow the fluid, which leads to higher levels of amniotic fluid in the womb.
- Pregnancy with multiples, such as twins.
- Rhesus disease – The developing fetus’ blood cells are attacked by the mother’s immune system.
- Lithium and maternal substance abuse
- Infections such as parvovirus, toxoplasmosis, rubella and cytomegalovirus
- In most cases of mild polyhydramnios, the cause is unknown.
The following criteria would place someone at higher risk: maternal diabetes, advanced paternal age, fertility treatments and incompatible blood types between mother and baby.
What are the complications of polyhydramnios?
The effects of polyhydramnios are dependent upon its severity. Maternal Complications include umbilical cord prolapse, PROM, preterm labor, amniotic fluid embolism, and placental abruption. Postpartum hemorrhage can also occur due to the overstretched uterus not contracting adequately after birth. There’s also a higher incidence of cesarean delivery due to abnormal fetal presentation, specifically a transverse position.
Fetal complications are varied and can include neural tube defects, GI obstructions, achondroplasia, cleft lip/palate and fetal hydrops, which is an abnormal fluid accumulation in the fetus.
Now that you have a background understanding of polyhydramnios, let’s talk through how to care for these patients using the Straight A Nursing LATTE method.
L: How does the patient LOOK? What are the signs and symptoms?
- The mother may complain of shortness of breath due to increased pressure on the uterus limiting lung expansion
- Edema of the lower extremities
- Unexplained weight gain, which is due to excess fluid
- Uterus that is larger than expected size (a rapid increase in size is common)
- Preterm contractions
- Hemorrhoids and constipation
- Varicose veins on the lower extremities
- With maternal diabetes, the mother will display the classic symptoms: polyphagia, polydipsia, and polyuria
- intense sudden pain and dark red blood with placental abruption
- Abnormal fetal heart rate due to cord prolapse (moderate to severe variable decelerations)
A: How do you ASSESS the patient for polyhydramnios?
- Measuring fundal height – it will be greater than expected for gestational age
- Get a full set of vital signs, paying special attention to blood pressure, which may be elevated.
- Weigh the patient, making note of any unexpected weight gain.
- Assess for edema, shortness of breath, constipation and other factors associated with increased pressure on internal organs.
- Use Leopold maneuvers to determine the fetal presentation. Remember that the extra fluid is basically more fluid for the baby to ‘swim’ in. They can end up transverse, or side-lying, or in other non-optimal birthing positions.
- Listen for the fetal heartbeat. Diminished sounds could indicate increased amniotic fluid.
T: What TESTS are conducted for polyhydramnios?
Many of the tests will be similar to those used for oligohydramnios. The gold standard diagnostic test is ultrasound, which measures the amount of amniotic fluid. It is important to note, however, that sonographer experience plays a key role in the accuracy of the measurements.
- Single deepest pocket measurement – In this measurement, the uterus is divided into four quadrants and the amniotic fluid volume is measured. A measurement over 8 cm is indicative of polyhydramnios (8 – 11 cm is mild, 12-15 is moderate and 16+ is severe). This is the simplest and most commonly used measurement technique.
- AFI (Amniotic Fluid Index) – With this technique, the practitioner measures the largest amniotic pocket in each of the four quadrants and adds them together. Mild polyhydramnios is an AFI of 25 – 30 cm, moderate is 30.1 – 35 cm, and severe is an AFI greater than 35.1 cm.
Ultrasound is also utilized to evaluate the fetus for conditions that can lead to polyhydramnios such as esophageal atresia.
Other tests include:
- Biophysical profile (BPP) – This is a type of ultrasound that assesses breathing, amniotic fluid volume, fetal tone (episodes of extension and flexion), and body movement.
- Non-Stress Test (NST) – This test involves the mother wearing a monitor to assess fetal heart rate while at rest for a period or 20 to 30 minutes (longer if the mother has been involved in a trauma, is bleeding, or has experienced decreased fetal movement).
- Gestational diabetes test (also known as a glucose tolerance test) and/or or HbA1C – These tests assess the mother for diabetes.
- ToRCH serology – To test for culprit infections.
- Nitrazine paper test can identify amniotic fluid when membrane rupture is suspected
- Amniocentesis – This procedure is conducted to test for any genetic conditions that can cause polyhydramnios. An amniocentesis can also provide valuable information about fetal lung maturity, as preterm labor is common.
- If fetal anemia or fetal hydrops are suspected, tests will be conducted to rule out hematologic and immunologic disorders.
T: What TREATMENTS are provided for polyhydramnios?
- Amnioreduction – In this procedure, excess amniotic fluid is removed. Note that this will need to be done repeatedly as the fluid will continue to build up. During the procedure, tocolytics will likely be used to prevent preterm labor from occurring. Other risks with this procedure are placental abruption, PROM and infection.
- In severe, emergent cases, a cesarean section may be needed for immediate removal of the baby.
- Fiber supplements – These may help prevent straining during bowel movements as this can put increased pressure on the uterus causing PROM.
- Position the mother for optimal blood return to reduce pressure on the cervix and lower extremities. This can be as simple as elevating the legs, but may require total bed rest.
- Diet & exercise and possible insulin for those with diabetes (Butkus, 2015).
Pharmacologic treatments include:
- Prostaglandin synthetase inhibitors (indomethacin and sulindac) can decrease the amount of urine the baby produces. Most cases of polyhydramnios respond to this treatment in about a week provided the cause is not related to fetal swallowing abnormalities or hydrocephalus.
- Tocolytic drugs may be used to stop contractions in preterm labor
- Steroids will help a preterm baby’s lungs rapidly mature if delivery is imminent
E: How do you EDUCATE the patient about polyhydramnios?
The most important things you can teach your patient are when they should call their doctor as serious complications can occur. Make sure your patient understands the signs and symptoms of preterm labor, PROM, placental abruption, umbilical cord protrusion and any other complication they are at risk for.
Other key teachings include:
- Diabetes teaching – If the cause of polyhydramnios is due to diabetes, you will provide extensive education on dietary guidelines, blood sugar testing, and proper medication administration.
- What to expect during various procedures. For example, the mother should know to empty her bladder before an amniocentesis, and to have a snack prior to a nonstress test as the baby is likely to be most active after eating.
- Indications, proper administration, and side effects of any medications. Indomethecin and sulindac should be taken with food to decrease GI upset and may increase hypoglycemic effects of insulin and oral antidiabetic medications.
- Substance abuse – Educate the mother on the importance of abstaining from drug use and provide resources as necessary. In the clinical setting, this includes a social work consult.
- If a baby is known to have an abnormality, the family will need extensive education regarding care and possible treatment options.
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