Low Albumin During Pregnancy: Common Causes and When It Matters

By Your Health Magazine Health Information Team

Low albumin in pregnancy is often caused by normal pregnancy-related changes, particularly increased blood plasma volume and changes in albumin metabolism. A mildly low result by itself usually does not mean something is wrong. However, the degree of the decrease, changes over time, symptoms, blood pressure, urine protein, and other liver or kidney test results determine whether it needs further evaluation.

Why Albumin Levels Often Fall During Pregnancy

Albumin is a protein made by the liver. It helps keep fluid inside blood vessels and carries hormones, vitamins, medicines, and other substances through the bloodstream. A serum albumin test is commonly included in a comprehensive metabolic panel or liver panel. The MedlinePlus albumin blood test guide notes that albumin levels are normally lower during pregnancy.

As pregnancy progresses, plasma volume expands. This dilutes many substances in the blood, including albumin. Pregnancy also affects how the body produces, distributes, and uses albumin. Research supports using pregnancy-specific reference intervals because normal laboratory values can change across pregnancy.

This means a result flagged as “low” against a general adult reference range may be expected for someone who is pregnant. There is no single albumin cutoff that can be interpreted appropriately without considering the trimester, the laboratory’s reference range, and the rest of the clinical picture.

Common Causes of Low Albumin During Pregnancy

Possible explanation	Clues a clinician may consider
Normal pregnancy physiology	Mild decrease, especially later in pregnancy, with otherwise reassuring blood pressure and test results
Inadequate food or protein intake	Severe nausea or vomiting, poor appetite, restricted diet, difficulty gaining expected weight, or food insecurity
Kidney protein loss	Protein in the urine, foamy urine, abnormal kidney tests, high blood pressure, or significant swelling
Liver disease	Abnormal liver enzymes, yellow skin or eyes, dark urine, itching, or upper abdominal discomfort
Inflammation or infection	Fever, illness, inflammatory disease, or changes in other blood tests
Digestive or absorption problems	Persistent diarrhea, unexplained weight loss, inflammatory bowel disease, or another condition that interferes with nutrient absorption
Excess fluid or recent IV fluids	A temporarily diluted blood sample after receiving substantial amounts of fluid

Low albumin does not automatically mean that a pregnant person is not eating enough protein. Albumin can fall because of dilution, inflammation, reduced liver production, or protein loss through the kidneys or digestive tract. Taking protein powders or making major dietary changes without knowing the cause may not correct the result and may not be appropriate for every pregnancy.

Low Blood Albumin Is Not the Same as Protein in Urine

These findings are related but different:

Serum albumin measures albumin circulating in the blood.
Urine protein or urine albumin measures protein being lost into the urine.

Healthy kidneys normally keep most albumin in the bloodstream. Kidney disease and some pregnancy complications can allow more protein to enter the urine, which may contribute to lower blood albumin when the loss is substantial.

Urine protein is particularly important when high blood pressure or symptoms of preeclampsia are present. Preeclampsia usually develops after 20 weeks of pregnancy, although it can also occur after delivery. Low serum albumin alone does not diagnose preeclampsia. Diagnosis is based on blood pressure and findings such as urine protein or evidence that the kidneys, liver, blood cells, lungs, brain, or other organs are affected.

When a Low Albumin Result May Matter

A clinician is more likely to investigate when albumin is substantially below the expected pregnancy range, continues to decrease, or occurs with concerning symptoms or other abnormal tests. Evaluation may include:

Reviewing the result against the laboratory’s pregnancy-appropriate range
Repeating the blood test to confirm the finding or follow the trend
Checking blood pressure
Testing urine for protein
Reviewing creatinine and other measures of kidney function
Checking liver enzymes, bilirubin, platelets, and other blood counts
Discussing vomiting, food intake, digestive symptoms, medications, and medical history

Swelling by itself does not identify the cause. Mild ankle and foot swelling is common later in pregnancy, while sudden swelling of the face or hands may be more concerning, especially when accompanied by high blood pressure, headache, vision changes, or upper abdominal pain.

What You Can Do About a Low Result

Bring the complete laboratory report to your obstetric clinician rather than focusing only on the value marked outside the standard range. Ask whether the result is expected for your stage of pregnancy and whether any related tests need to be reviewed or repeated.

Continue balanced prenatal nutrition as recommended by your healthcare team. If severe nausea, vomiting, food restrictions, digestive disease, or difficulty accessing nutritious food is affecting your intake, an obstetric clinician or registered dietitian can help. Do not start high-dose supplements or change prescription medicines solely because of an albumin result without professional guidance.

Keeping regular prenatal appointments allows blood pressure, urine findings, fetal growth, and symptoms to be assessed together. MedlinePlus provides additional pregnancy and prenatal care information. For related practical guidance, see these tips on safe sleep positioning and nighttime comfort during pregnancy.

When to Seek Care

Contact your obstetric clinician promptly if a low albumin result occurs with worsening swelling, foamy urine, decreased urination, persistent vomiting, jaundice, dark urine, significant weakness, or unexplained weight loss.

Seek urgent evaluation for possible preeclampsia if you develop a severe or persistent headache, vision changes, sudden swelling of the face or hands, upper abdominal or shoulder pain, trouble breathing, or nausea and vomiting that begins in the second half of pregnancy. The American College of Obstetricians and Gynecologists provides a detailed overview of preeclampsia warning signs and evaluation. These symptoms can also occur during the weeks after childbirth.

Albumin is only one part of the assessment. In many pregnancies, a mild decrease is an expected laboratory change. The result matters most when it is interpreted alongside gestational age, symptoms, blood pressure, urine protein, and liver and kidney function.