What is a normal ALT level for a pregnant woman?

November 29, 2025 •

4 min read

According to one study, up to 12% of pregnant women can have elevated liver function tests, yet understanding what is a normal ALT level for a pregnant woman is crucial for monitoring liver health. This guide explains the typical ranges and helps distinguish normal fluctuations from potential complications that require medical attention.

Quick Summary

Normal ALT levels can fluctuate and may even be slightly lower during pregnancy due to hemodilution, but values outside the standard range may indicate underlying liver stress or conditions like HELLP syndrome, ICP, or AFLP. Abnormal results and associated symptoms require prompt medical evaluation.

Key Points

Normal Range: Healthy pregnant women typically have ALT levels within or slightly below the normal range for non-pregnant women, which is often around 7-35 U/L.
Trimester Variation: ALT levels may naturally decrease with the progression of pregnancy due to increased blood volume, or hemodilution.
Elevated Levels: An ALT level above 40 U/L, especially with symptoms, warrants further medical evaluation for potential liver issues.
Associated Conditions: Significantly elevated ALT can point to serious pregnancy-specific conditions like HELLP syndrome, intrahepatic cholestasis of pregnancy (ICP), or acute fatty liver of pregnancy (AFLP).
Seek Medical Advice: Any unexplained rise in ALT levels or accompanying symptoms like severe itching, abdominal pain, or jaundice should prompt immediate consultation with a healthcare provider.

Understanding Your Liver and ALT

Alanine aminotransferase (ALT), also known as SGPT, is an enzyme primarily located in the liver cells that is vital for converting food into energy. When liver cells are damaged, ALT is released into the bloodstream, and higher-than-normal levels can indicate liver injury or disease. During pregnancy, the liver experiences increased metabolic demands due to hormonal changes and increased blood volume. For this reason, monitoring ALT levels is an important part of prenatal care, though interpretations must be made with the physiological changes of pregnancy in mind.

Normal ALT Ranges in Pregnancy by Trimester

While general reference ranges for non-pregnant women typically fall between 7-35 U/L, normal ALT levels for pregnant women can differ and often trend lower as pregnancy progresses. This is partly due to hemodilution, where the increase in blood volume dilutes the concentration of substances in the blood.

Table: Normal ALT Ranges by Trimester (Example Range)


Stage	Example ALT Range (U/L)	Reason for Variation
First Trimester	3 - 30	Early pregnancy levels, influenced by hormones.
Second Trimester	2 - 33	Blood volume increases, potentially lowering concentrations.
Third Trimester	2 - 25	Further blood dilution effects and physiological changes.
Non-Pregnant	7 - 41	The standard reference range for comparison.

It is crucial to remember that reference ranges can vary between laboratories. Your healthcare provider will interpret your results based on the specific lab's standards, your gestational age, and your overall clinical picture.

When is an Elevated ALT Level a Concern?

An ALT level that exceeds the established upper limit for pregnancy is considered abnormal and should prompt further investigation. According to some experts, an ALT level above 40 U/L warrants medical evaluation, especially if accompanied by symptoms. Elevated ALT levels can be categorized by their magnitude:

Mildly Elevated: Levels between 36-70 U/L may indicate early liver stress.
Moderately Elevated: Levels from 71-200 U/L suggest active liver disease.
Severely Elevated: Levels >200 U/L signal serious liver dysfunction and require immediate attention.

It's important to note that a rise in ALT is not always indicative of a severe condition but can also be caused by viral infections, intense exercise, or certain medications.

Causes of High ALT During Pregnancy

Elevated ALT can result from conditions unique to pregnancy, pre-existing liver issues, or coincidental problems. A proper diagnosis requires a comprehensive evaluation by a healthcare provider.

Pregnancy-Specific Liver Conditions

Intrahepatic Cholestasis of Pregnancy (ICP): A liver disorder affecting 1-2% of pregnancies, typically presenting in the second or third trimester with severe itching, particularly on the palms and soles. ALT is usually mildly to moderately elevated.
HELLP Syndrome: A life-threatening complication, often related to preeclampsia, occurring in the third trimester. It involves Hemolysis (breakdown of red blood cells), Elevated Liver enzymes (ALT can range from 100-1000 U/L), and Low Platelets.
Acute Fatty Liver of Pregnancy (AFLP): A rare but serious disorder typically seen in the third trimester. Symptoms include nausea, vomiting, abdominal pain, and jaundice, with moderately elevated ALT levels (200-500 U/L).
Hyperemesis Gravidarum: Severe morning sickness in the first trimester that can cause mild, transient ALT elevation that resolves with treatment and improved nutrition.

Coincidental or Pre-existing Conditions

Viral Hepatitis: Infections like Hepatitis B or C can flare up or be discovered during pregnancy, leading to elevated ALT.
Medication-Induced Liver Injury: Certain medications, including some antibiotics and pain relievers like acetaminophen in large doses, can affect ALT levels.
Gallstones: Hormonal changes can increase the risk of gallstone formation, which can block bile ducts and cause liver enzyme elevation.

Symptoms Associated with Abnormal ALT

While elevated ALT alone doesn't cause symptoms, the underlying condition does. It is crucial to be aware of the following signs that warrant medical attention:

Severe, persistent itching, especially on the hands and feet.
Pain in the upper right side of the abdomen.
Jaundice (yellowing of the skin and eyes).
Persistent nausea and vomiting.
Unusual fatigue or malaise.
Dark urine or pale stools.

Diagnosis and Treatment

If your ALT levels are high, your doctor will likely perform a series of tests to determine the cause. This may include additional blood work, such as a complete metabolic panel, viral hepatitis screening, or bile acid tests for suspected ICP. Ultrasound or other imaging studies may also be used to visualize the liver and biliary tree.

Treatment depends entirely on the specific diagnosis. For severe, pregnancy-specific conditions like HELLP or AFLP, the definitive treatment is often prompt delivery of the baby, regardless of gestational age, to prevent serious maternal and fetal complications. For milder cases, such as those related to hyperemesis gravidarum, supportive care and dietary management are often sufficient.

What to Expect Postpartum

For most women with pregnancy-related liver conditions, ALT levels will typically return to normal within days to weeks after delivery as the liver heals. However, postpartum monitoring is essential to ensure complete resolution of liver dysfunction. Women with a history of ICP have an increased risk of gallstones and recurrence in future pregnancies, so follow-up with a healthcare provider is recommended. For women with persistently elevated ALT levels after birth, further evaluation for chronic liver disease is necessary. For more information on liver health during pregnancy, you can visit the National Institutes of Health website(https://www.ncbi.nlm.nih.gov/books/NBK6005/).

Conclusion

Understanding what constitutes a normal ALT level for a pregnant woman is a crucial part of proactive prenatal care. While normal physiological changes can alter liver enzyme levels, significant elevations should always be promptly investigated by a healthcare professional. Recognizing potential symptoms and acting quickly can prevent serious complications for both mother and baby. By monitoring liver health, pregnant women can ensure the best possible outcomes for their pregnancy and overall well-being.

Frequently Asked Questions

The normal ALT range during pregnancy can vary by lab, but is often cited as being within or slightly lower than the non-pregnant range of 7-35 U/L. Levels tend to decrease throughout gestation due to hemodilution, so trimester-specific reference ranges are often used, such as 3-30 U/L in the first trimester and 2-25 U/L in the third.

An elevated ALT level can signal liver stress or damage. During pregnancy, this could be due to pregnancy-specific conditions like HELLP syndrome, intrahepatic cholestasis of pregnancy (ICP), or acute fatty liver of pregnancy (AFLP). It could also indicate a pre-existing liver disease or a medication side effect.

You should be concerned if your ALT levels are above 40 U/L, particularly if you experience symptoms like persistent itching (especially palms/soles), right upper quadrant abdominal pain, or jaundice (yellow skin or eyes). Levels >100 U/L are particularly concerning and warrant urgent medical attention.

Elevated ALT levels themselves do not directly harm the baby, but the underlying conditions causing the elevation can pose risks. Conditions like HELLP syndrome, ICP, and AFLP can lead to premature birth, fetal distress, or stillbirth if not treated promptly.

Treatment depends on the underlying cause. For severe conditions like HELLP or AFLP, immediate delivery of the baby is often necessary. For less severe cases like ICP, medication such as ursodeoxycholic acid may be used, and for hyperemesis gravidarum, supportive care like rehydration is the main approach.

For most pregnancy-specific liver conditions, ALT levels typically normalize within days to weeks after delivery. Your doctor will monitor your levels postpartum to confirm that they have returned to a healthy range.

Abnormal liver function tests are not uncommon during pregnancy, occurring in about 3-5% of pregnancies. However, not all abnormalities indicate a severe condition, and interpretation must be done by a medical professional considering the physiological changes of pregnancy.