BACKGROUND AND PURPOSE:

• Abnormal placental growth factor (PlGF) may be useful as a diagnostic biomarker for preeclampsia, but has yet to be incorporated into guidelines due to lack of evidence regarding clinical utility
• Hayes-Ryan et al. (BMJ, 2021) assessed whether the addition of PIGF to current clinical practice in the setting of preeclampsia before 37 weeks could improve outcomes

METHODS:

• Stepped wedge cluster randomized control trial
  • Trial conducted in Ireland
  • Investigator led
  • 7 largest maternity units in Ireland
• Participants
  • Singleton pregnancy between 20w0d and 36w6d  
  • Signs or symptoms suggestive of evolving preeclampsia
• Intervention
  • Usual care only
  • Usual care plus point-of-care PlGF testing
• Study design
  • Each maternity hospital acted as a cluster | All clusters started as a control and then transitioned at random to PlGF intervention at pre-specified time points
  • Usual care: Based upon NICE guidelines for preterm preeclampsia
  • Point-of care PlGF: Increased investigation and frequency of review for abnormal or highly abnormal PlGF result (<100 pg/mL and <12 pg/mL respectively) | Final decisions including when to deliver based on clinician’s judgement
  • Analysis was on an individual participant level using mixed-effects Poisson regression adjusted for time effects by intention-to-treat
• Primary outcomes
  • Composite maternal morbidity
  • Composite neonatal morbidity

RESULTS:

• Usual care: 1202 participants | PlGF testing: 1017 participants
• The addition of point-of-care PlGF testing did not lead to a difference in
  • Maternal morbidity
    • Usual care: 38%
    • PlGF testing: 32%
    • Adjusted risk ratio (aRR) 1.01 (95% CI, 0.76 to 1.36); P=0.92
  • Neonatal morbidity
    • Usual care: 43%
    • PlGF testing: 47%
    • aRR 1.03 (95% CI, 0.89 to 1.21); P=0.67

CONCLUSION:

• Point-of-care PlGF testing during clinical work-up for women presenting with suspected preterm preeclampsia did not improve maternal or neonatal outcomes
• The authors conclude that while the results of this study do not support the integration of PlGF testing in clinical assessment, neither do they exclude a potential benefit
• The authors state

Although we supplied a management algorithm to clinicians to incorporate PlGF based testing into clinical practice, this was a suggested algorithm only and adherence was not mandatory

Fidelity to the algorithm was not assessed. Hence this trial demonstrates a pragmatic evaluation of PlGF based testing effectiveness rather than its efficacy

Learn More – Primary Sources:

Placental growth factor in assessment of women with suspected pre-eclampsia to reduce maternal morbidity: a stepped wedge cluster randomised control trial (PARROT Ireland)

Related ObG Topics:

Point-of-Care Test for Preeclampsia: Glycosylated Fibronectin

Does Placental Growth Factor Lead to a Quicker Diagnosis in Women with Suspected Pre-Eclampsia?

Follow Up on the PARROT Trial: Is Placental Growth Factor Testing for Preeclampsia Cost-Effective?

Results from the SPREE Trial: How Does First Trimester Preeclampsia Screening Compare to Current Guidelines?