Bilirubin

Bilirubin is a yellow pigment produced by red blood cell breakdown. It is often used to help assess liver function and hemolysis in pregnancy. In this article, we’ll explore optimal bilirubin levels during pregnancy and potential causes of abnormal levels.

Bilirubin Testing

Total bilirubin measures the amount of conjugated and unconjugated bilirubin in the blood sample. It is an analyte found on the comprehensive metabolic panel (CMP).

80% of bilirubin is made from the breakdown of hemoglobin in senescent red blood cells and prematurely destroyed erythroid cells in the bone marrow. The remainder originates from the turnover of various heme-containing proteins found in other tissues, primarily the liver and muscles.

Hemoglobin is broken down into its heme and globin components. The heme part is further converted into biliverdin. Biliverdin is green in color. An enzyme called biliverdin reductase converts biliverdin into bilirubin, a yellow pigment. This process involves reducing biliverdin and changing its color from green to yellow. Bilirubin is initially insoluble in water, so it binds to albumin in the blood. This form of bilirubin is called unconjugated bilirubin and is transported to the liver.

Unconjugated is taken to the liver and combined with glucuronic acid, making it water-soluble. This conjugated bilirubin is then excreted into bile. 

​Currently there is not enough data to recommend adjusted ranges from the current accepted ranges in pregnancy. 

Bilirubin in Pregnancy

Total bilirubin concentrations are decreased during all three trimesters of pregnancy.

High Bilirubin in Pregnancy

Any elevation in serum bilirubin should be considered pathogenic in pregnancy. 

Most Common Causes of High Bilirubin in Pregnancy

• Hemolysis
• Liver Disease/Inflammation
• Intrahepatic Cholestasis of Pregnancy (ICP)
• Thalassemia
• Sickle Cell Anemia
• Gilbert's Syndrome
• Mycotoxin Exposure
• Environmental Chemical Exposure
• Iron Overload/Hemochromatosis
• Nutritional Deficiencies (manganese, zinc, vitamin B12 (cobalamin))

Low Bilirubin in Pregnancy

​​There is limited data on the consequences of low bilirubin in pregnancy.

Most Common Causes of Low Bilirubin in Pregnancy

• Severe Hemolytic Anemia
• Low Hemoglobin
• Certain Medications (antibiotics, antivirals)
• Nutritional Deficiencies (vitamin B6 (pyridoxine), iron)
• Zinc Supplement Overdose

Did You Know...

...I offer an advanced lab analysis in pregnancy course for professionals?
MEAC approved for 12 CE credits

See Course Details Here

---

Copyright © 2024 Functional Maternity, all rights reserved.

Medical Disclaimer:
This content is for educational purposes only and is intended for licensed medical professionals. It is based on current research, subject to change, and not intended to diagnose, treat, or prevent any medical condition. This information does not replace consultation with a qualified healthcare provider. Seek professional medical evaluation and treatment from a licensed provider. Use of this information is at your own risk.

---