Objectives: Serum lactate dehydrogenase has been extensively studied in
hypertensive disorders of pregnancy. However, to date, its clinical
usefulness in the field remains unknown. The present meta-analysis has
been designed to evaluate differences in serum LDH values among patients
with hypertensive disorders of pregnancy and to help determine its
diagnostic accuracy as well its predictive accuracy in determining
adverse pregnancy outcomes. Methods: We searched Medline, Scopus,
Clinicaltrials.gov, EMBASE, Cochrane Central Register of Controlled
Trials CENTRAL and Google Scholar databases from their inception till
March 18, 2021. Meta-analysis was performed using the meta and metafor
functions in Rstudio. Pooled mean differences (MD) were calculated with
the Hartung-Knapp-Sidik-Jonkman. Meta-regression analyses, publication
bias assessment and Trim and Fill function were also performed. The
adequacy of the sample size was evaluated with Trial Sequential
Analysis. Results: Fifty-two articles were included that comprised 5,340
women with hypertensive disorders of pregnancy and 2,890 healthy
controls. The meta-analysis revealed significant differences among
patients with preeclampsia (either mild or severe) compared to controls,
as well as among patients with mild and severe preeclampsia. Significant
asymmetry was noted after examining funnel plots, however, and the trim
and fill analysis revealed that differences were significant only among
cases with severe preeclampsia and healthy controls. Morbidity outcomes
increased with LDH levels > 600 IU/L and particularly when
these exceeded 800 IU/L. However, confidence and prediction intervals
indicated an underpowered sample size for the accurate determination of
the odds of developing maternal morbidity. Conclusions: Despite the
extensive research in the field of hypertensive disorders of pregnancy,
there is still lack of evidence concerning the diagnostic performance of
serum LDH in clinical practice; hence, research should expand in this
direction to evaluate its clinical utility.