Altered Cord Blood Enzyme Activities in Preeclampsia Without Severe Features: A Comparative Observational Study

Background and Objectives: Preeclampsia (PE) is associated with placental dysfunction, endothelial abnormalities, and disturbed redox homeostasis, but enzyme activity patterns in the fetal circulation remain incompletely characterized. This study aimed to compare selected cord blood enzyme activities between pregnancies complicated by PE without severe features and normotensive pregnancies. Materials and Methods: This prospective observational comparative study included 122 participants: 54 women with PE without severe features and 68 women with normotensive pregnancies. All participants delivered vaginally at 37 weeks 1 day to 38 weeks 0 days of gestation. Plasma butyrylcholinesterase (BChE) and erythrocyte acetylcholinesterase (AChE), carbonic anhydrase (CA), glucose-6-phosphate dehydrogenase (G6PD), and glutathione reductase (GR) activities were measured spectrophotometrically. Groups were compared using the two-sided Mann-Whitney U test. Results: Compared with the normotensive pregnancy group, the PE group had lower median AChE (17.60 vs. 26.49 U/g Hb), BChE (1.060 vs. 1.340 EU/mg protein), G6PD (13.79 vs. 15.04 U/g Hb), and GR activities (0.880 vs. 1.075 EU/mg protein), corresponding to reductions of 33.6%, 20.9%, 8.3%, and 18.1%, respectively. Median CA activity was 3.1% higher in the PE group (8.615 vs. 8.360 EU/mg protein). All between-group differences were statistically significant (all p < 0.001). Conclusions: PE without severe features was associated with an enzyme-specific cord blood profile characterized by reduced cholinesterase and redox-related enzyme activities and increased CA activity. These findings support further investigation of fetal enzymatic alterations in PE.