Nursing care
HELLP vs preeclampsia: how the labs separate them and what the nurse watches
Written and reviewed by Hannah Nguyen, MSN, RN, CPN · 4 min read · Updated November 2026
Short answer
Preeclampsia is defined by new high blood pressure after 20 weeks with protein in the urine or signs of organ damage. HELLP is a severe variant defined by labs: hemolysis, elevated liver enzymes and a low platelet count. Some clients with HELLP have neither high blood pressure nor proteinuria, so the labs, not the cuff, make the call.
Blood work, not the cuff, makes the HELLP call
Preeclampsia is a blood pressure diagnosis. MSD Manuals defines it as new or worsening hypertension after 20 weeks of gestation, a systolic of 140 or diastolic of 90 or higher on two readings at least 4 hours apart, along with proteinuria or signs of organ damage.
HELLP is a lab diagnosis. The name spells it out: Hemolysis, Elevated Liver enzymes, Low Platelets. MSD Manuals lists a platelet count under 100,000 and a lactate dehydrogenase (LDH) of 600 IU/L or more, with raised liver enzymes. LDH climbs because red cells are breaking apart, which is the hemolysis part of the name.
Can you have HELLP without preeclampsia?
Yes, and this is where students lose points. MedlinePlus describes HELLP as a variant of preeclampsia that develops in roughly 10 to 20 percent of people who have preeclampsia or eclampsia. Yet MSD Manuals notes that some clients with HELLP have neither hypertension nor proteinuria, which makes the atypical case easy to miss.
So a pregnant client in the third trimester with worsening nausea, malaise and upper right abdominal pain should not be reassured because her pressure is only mildly raised or even normal. Those complaints can sound like a stomach bug. The platelet count and liver enzymes decide whether this is HELLP.
Symptoms that overlap and timing that surprises students
Both conditions can cause headache, visual changes and swelling, and right upper quadrant or epigastric pain is listed by MSD Manuals as a severe feature of preeclampsia. Pain alone therefore cannot separate them. MedlinePlus adds the HELLP picture of fatigue, nausea and vomiting that keeps getting worse, and pain in the upper right or middle abdomen.
Timing matters too. MedlinePlus states HELLP most often appears between 26 and 40 weeks but can occur in the week after birth. MSD Manuals describes preeclampsia developing postpartum as well, usually within 4 days and up to 6 weeks. A client who delivered yesterday is still at risk for both.
Nursing priorities for each
For preeclampsia, the nurse monitors blood pressure trends, urine output, reflexes, headache and vision, and gives magnesium sulfate when ordered for seizure prevention, watching for magnesium toxicity. Delivery is the only definitive treatment, with timing based on gestational age and severity.
HELLP adds bleeding risk on top of all of that. Watch for bruising, bleeding gums, oozing from IV sites and worsening abdominal pain with falling blood pressure. MedlinePlus lists complications including bleeding into the liver, liver failure, disseminated intravascular coagulation, kidney failure and placental abruption. Report a falling platelet count promptly; delivery is again the main treatment.
Hypothetical practice scenario
Hypothetical scenario, not a real exam item: a client at 34 weeks reports nausea and right upper abdominal pain. Blood pressure is 138/86. Labs show platelets of 82,000 and raised liver enzymes. Which finding is most concerning: the pressure, the nausea, or the lab results?
The labs. A pressure under 140/90 does not settle anything here, and choosing it as the main issue reflects thinking that HELLP needs severe hypertension first. The nausea matters, but it is a symptom with many causes. The low platelets and raised enzymes point to HELLP and need urgent reporting.
Sources and further reading
MSD Manual Professional Version: Preeclampsia and Eclampsia. Blood pressure criteria, severe features including RUQ pain, HELLP lab criteria (LDH and platelets), HELLP without hypertension or proteinuria, postpartum timing, magnesium and delivery.
MedlinePlus: HELLP syndrome. Definition, 10 to 20 percent of preeclampsia cases, symptoms, 26 to 40 week timing and postpartum onset, treatment and complications.
The next step on this is the same as on everything else here: answer questions and read the rationales. Our maternity and newborn practice questions are the closest set to what this page covers.
Common questions
What labs show HELLP syndrome?
A falling platelet count, raised liver enzymes and markers of hemolysis such as a high LDH. MSD Manuals lists platelets under 100,000 and LDH of 600 IU/L or more. A complete blood count and liver panel are the core tests the nurse should expect to trend.
What does HELLP stand for?
Hemolysis, Elevated Liver enzymes and Low Platelets. Each letter group names a lab finding, which is why the diagnosis rests on blood work rather than on blood pressure or symptoms alone.
Is HELLP worse than preeclampsia?
HELLP is treated as a severe form of the disorder because it adds bleeding risk and liver injury. MedlinePlus lists liver failure, DIC and placental abruption among its complications. Prompt delivery is the main treatment once it is identified.