HELLP syndrome

By trimester

Weeks 1–13

1st trimester

HELLP is uncommon this early. Severe upper-abdominal pain, persistent vomiting with marked illness, jaundice, heavy bleeding, severe headache, or neurologic symptoms still need urgent assessment because other serious conditions can resemble HELLP.

Weeks 14–27

2nd trimester

HELLP can occur in the second half of pregnancy, including before classic third-trimester timing. New right-upper-abdominal or epigastric pain with headache, vision changes, nausea, or unusual bruising warrants same-day hospital assessment and laboratory testing.

Weeks 28–birth

3rd trimester

Most HELLP presentations occur in late pregnancy. Do not wait for a routine visit or assume a normal home blood-pressure reading excludes it. Maternal laboratory findings and fetal assessment guide urgent obstetric decisions.

What does the evidence show for HELLP syndrome?

• HELLP stands for hemolysis, elevated liver enzymes, and low platelet count. Symptoms can include right-upper or mid-abdominal pain, worsening nausea or vomiting, headache, vision changes, fatigue, and easy bleeding, and the condition can also first appear after delivery. 1
• NICHD notes that HELLP can be the first warning of a hypertensive pregnancy complication and can occur without high blood pressure or protein in the urine. Bruising, upper-abdominal pain, nausea or vomiting, headache, and extreme fatigue warrant immediate clinical attention. 2
• Evaluation uses a complete blood count and platelet count, liver tests, bilirubin and other hemolysis markers, kidney assessment, and, when indicated, coagulation tests. No symptom or home blood-pressure reading can confirm or exclude the laboratory triad. 3
• A clinical review reports that about 15% to 20% of patients with HELLP may not have preceding hypertension or proteinuria. It also describes onset most often between 28 and 37 weeks or within seven days postpartum, while acknowledging variable presentations. 3
• An older narrative review similarly found that hypertension or proteinuria may be absent in a minority of cases and emphasized overlap with acute fatty liver of pregnancy, thrombotic microangiopathies, hepatitis, and other conditions. Its frequency estimates combine heterogeneous historical definitions rather than a current controlled cohort. 4

When should I call my provider about HELLP syndrome?

New severe or persistent right-upper-abdominal or upper-middle abdominal pain in pregnancy or the postpartum period needs immediate hospital assessment, especially with nausea, vomiting, headache, or vision changes. Seizure, fainting, confusion, trouble breathing, chest pain, heavy bleeding, or rapidly worsening illness is an emergency. Call emergency services. Unusual bruising, bleeding that does not stop, jaundice, markedly reduced urine, or a severe headache that does not improve requires urgent assessment even if a home blood-pressure value is not high. Trust your read on your own body. If something feels off beyond the list above, please consult your healthcare provider rather than waiting it out.