PURPOSE:

• Using a large national database, Lisonkova et al. sought to determine the risk factors associated with HELLP syndrome (hemolysis, elevated liver enzymes and low platelets) and associated maternal and perinatal outcomes

METHODS:

• Retrospective population‐based cohort study (2012 – 2016)
• Participants
  • Singleton | ≥24 weeks
  • Both live birth or stillbirth included
• HELLP syndrome definition: CD‐10‐CA diagnostic codes
  • The Canadian Institute for Health Information maintains a Discharge Abstract Database that collects data from approximately 98% of all births (excluding Quebec)
• Statistical analysis
  • Logistic regression to determine independent risk factors and address confounding
  • Adjusted odds ratio (AOR) used to identify associations with adverse outcomes
• Primary outcome
  • Severe maternal morbidity: Includes conditions that result in extended hospital stay and significant sequelae (e.g. eclampsia, maternal hemorrhage etc.)
  • Severe fetal and infant outcomes: Includes conditions associated with serious adverse events (e.g. stillbirth, neonatal death, bronchopulmonary dysplasia, retinopathy of prematurity, RDS, IVH, sepsis etc.)

RESULTS:

• Data from 1,078,323 deliveries were included
• Incidence of HELLP: 2.5 per 1000 singleton deliveries

Risk Factors

• HELLP associated with the following risk factors
  • Age: ≥35 years: P value for trend <0.001
  • Rural residence: AOR 1.21 (95% CI, 1.07 to 1.35)
  • Nulliparity: AOR 3.20 (95% CI, 2.89 to 3.54)
  • Parity ≥4: AOR 1.68 (95% CI, 1.15 to 2.44)
  • Pre‐pregnancy hypertension: AOR 1.79 (95% CI, 1.33 to 2.40)
  • Pre-pregnancy diabetes: AOR 2.90 (95% CI, 2.29 to 3.67)
  • Gestational hypertension: AOR 1.71 (95% CI, 1.48 to 1.97)
  • ART: AOR 1.63 (95% CI, 1.36 to 1.96)
  • Chronic cardiac conditions (chronic heart failure): AOR (95% CI, 1.14 to 4.26)
  • SLE: AOR 4.42 (95% CI, 2.21 to 8.86)
  • Obesity: AOR 1.58 (95% CI, 1.28 to 1.95)
  • Chronic hepatic conditions (e.g., cirrhosis): AOR 7.18 (95% CI, 4.20 to 12.3)
  • Placental disorders (e.g. fetomaternal transfusion or placenta accreta): AOR 3.54 (95% CI, 2.84 to 4.41) | Placental previa was not associated with HELLP
  • Congenital anomalies: AOR 2.17 (95% CI, 1.94 to 2.43)
• Features that reduced risk: PROM and age <25 years

Outcomes

• Maternal mortality: Unadjusted due to low numbers but at minimum OR 11.5 (95% CI 1.58–84.3)
• HELLP associated with severe maternal morbidity (e.g., severe preeclampsia, eclampsia, hemorrhage, hysterectomy, sepsis, embolism, cardiac, renal and hepatic failure)
  • Non-HELLP: 9.6 per 1000
  • HELLP: 121.7 per 1000
  • AOR 12.5 (95% CI, 11.1 to 14.1)
• HELLP associated with perinatal mortality (stillbirth or neonatal death)
  • Non-HELLP: 4.3 per 1000
  • HELLP: 21.0 per 1000
  • AOR 4.5 (95% CI, 3.5 to 5.9)
• HELLP associated with perinatal mortality/ severe neonatal morbidity (bronchopulmonary dysplasia, retinopathy of prematurity, and RDS)
  • Non-HELLP: 21.2 per 1000
  • HELLP: 202.4 per 1000
  • AOR 10.7 (95% CI, 9.7–11.8)
• Preterm birth more common with HELLP (P<0.001)
  • Non-HELLP: 6.1%
  • HELLP syndrome: 52.9%
  • AOR 16.5 (95% CI, 15.3 to 17.9)

CONCLUSION:

• There is a 10‐fold higher risk for maternal mortality in the setting of HELLP
• Aside from well-known risk factors such as gestational hypertension, the authors also found significant independent pre-pregnancy risk factors such as diabetes, cardiac and hepatic disease
• Both nulliparity and parity ≥4 were associated with HELLP
• The authors state

This was an exploratory study

Further research is required to refine our findings and determine whether HELLP syndrome at term can be successfully predicted and prevented by early delivery in women with specific chronic conditions or pregnancy complications that place them at high risk for the syndrome

Learn More – Primary Sources:

Maternal risk factors and adverse birth outcomes associated with HELLP syndrome: a population‐based study

Related ObG Topics:

Diagnosing Preeclampsia – Key Definitions and ACOG Guidelines

ACOG Preeclampsia Guidelines: Antenatal Management and Timing of Delivery

ACOG Guidance: Emergency Treatment for Severe Hypertension in Pregnancy