Can pregnancy cause hypoalbuminemia?

Pregnancy Causes Hypoalbuminemia

Yes, pregnancy normally causes decreased albumin levels, particularly in the second and third trimesters due to hemodilution from increased plasma volume. 1 This is a physiological change of normal pregnancy and should not be confused with pathological hypoalbuminemia.

Physiological Changes in Albumin During Pregnancy

Normal Albumin Changes

• Albumin levels decrease during the second half of pregnancy due to hemodilution 1
• According to the American Association for the Study of Liver Diseases, this is an expected physiological change 1
• In the third trimester, serum albumin typically decreases to levels between 3.0-3.5 g/dL 2
• A cross-sectional study found mean albumin levels of 33.41 ± 4.62 g/L in pregnant women compared to 37.09 ± 4.21 g/L in non-pregnant controls 2

Mechanism

• Increased plasma volume during pregnancy (expands by up to 40% by 24 weeks) 1
• Decreased hepatic synthesis relative to expanded blood volume
• Altered Starling forces that favor a narrowing of the oncotic pressure-wedge pressure gradient 1
• Increased renal blood flow (by approximately 40%) to accommodate maternal role in fetal detoxification 1

Clinical Implications

Distinguishing Normal from Pathological Hypoalbuminemia

• Mild hypoalbuminemia (3.0-3.5 g/dL) is seen in both normal pregnancy and early preeclampsia 3
• Albumin levels below 3.0 g/dL may indicate severe preeclampsia 3
• Significant hypoalbuminemia (<2.0 g/dL) is associated with complications of preeclampsia including thrombocytopenia, elevated liver enzymes, and severe proteinuria 4

Conditions That May Exacerbate Pregnancy-Related Hypoalbuminemia

• Preeclampsia - can cause more severe hypoalbuminemia due to proteinuria and endothelial dysfunction 5
• Diabetic nephropathy - women with pre-existing microalbuminuria experience a 6.7-fold increase in urinary albumin excretion during pregnancy compared to a 3.8-fold increase in women without microalbuminuria 6
• Minimal change nephrotic syndrome - can present with severe hypoalbuminemia during pregnancy 7

Monitoring and Management

When to Be Concerned

• Albumin levels <3.0 g/dL warrant further investigation, especially when accompanied by:
  • Hypertension (≥140/90 mmHg) 5
  • Proteinuria (≥0.3g/24h or albumin-to-creatinine ratio ≥30 mg/mmol) 5
  • Edema beyond physiological pregnancy edema
  • Liver function abnormalities

Monitoring Recommendations

• Routine prenatal care should include assessment of albumin levels, especially in high-risk pregnancies
• More frequent monitoring is indicated for women with:
  • Pre-existing kidney disease
  • Diabetes mellitus (particularly with microalbuminuria) 6
  • History of preeclampsia
  • Chronic hypertension

Clinical Pearls and Pitfalls

Common Pitfalls

• Misinterpreting physiological hypoalbuminemia as pathological
• Failing to recognize that severe hypoalbuminemia (<2.0 g/dL) is not normal in pregnancy and requires evaluation
• Not considering hypoalbuminemia as an early sign of developing preeclampsia 3

Important Considerations

• Physiological edema in pregnancy is partly related to lower serum albumin 2
• Hypoalbuminemia may affect drug binding and increase free fraction of medications during pregnancy 1
• After delivery, albumin levels typically return to pre-pregnancy values within 12 weeks 6

In summary, mild hypoalbuminemia is a normal physiological change during pregnancy due to hemodilution, but significant decreases in albumin levels may indicate underlying pathology such as preeclampsia or kidney disease that requires further evaluation and management.