Assessing iron metabolism parameters in pregnant women with different preeclampsia phenotypes

Aim: to determine iron metabolism parameters in the blood of pregnant women with different preeclampsia (РЕ) phenotypes.

Materials and Methods. A single-center prospective comparative case-control study was conducted that assessed clinical, anamnestic, laboratory, and instrumental data of 95 pregnant women, divided into two groups: the main group (70 pregnant women with diagnosed early- and late-onset PE) and control group (25 women of similar age without significant extragenital and gynecological pathology, without PE) with a favorable outcome of pregnancy and childbirth. The analysis was conducted in main group depending on PE manifestation. It was found that in main group 19/70 (27.1 %) pregnant women were with early-onset PE; 16/19 (84.2 %) of them had severe PE with fetal growth restriction (FGR), the remaining 3/19 (15.8 %) women had moderate PE without FGR. Late PE manifestation was observed in 51/70 (72.9 %) pregnant women; 6/51 (11.8 %) had severe PE with FGR, 45/51 (88.2 %) had moderate PE. In late-onset PE, one FGR case was identified at 35+5 weeks of gestation. In main group, 23 (32.9 %) observations with PE and FGR were found. Iron metabolism parameters (hemoglobin level and erythrocyte characteristics, serum iron content, transferrin, ferritin, latent iron-binding capacity of blood serum, haptoglobin, soluble transferrin receptors and hepcidin 25) were studied thoroughly in patients with earlyand late-onset PE.

Results. The ambiguity and divergence of iron metabolism parameters in developing early- and late-onset PE were demonstrated. Among women with subsequent manifestation of both early- and late-onset PE at the onset of the second trimester of pregnancy, 8/70 (11.4 %) patients received iron therapy. Our results indicate not detected iron deficiency, but rather a completely different value for iron metabolism markers in PE pathogenesis. In particular, in early-onset PE, the ferritin level was 3.46 times higher than that of in the second trimester of uncomplicated pregnancy, whereas in late-onset PE, it was 5.78 times higher than in the third trimester in control group. In early-onset PE, the level of transferrin receptors was 1.78 mg/L vs. 0.75 mg/L in women with uncomplicated pregnancy at the same time, which is 2.37 times higher. In late-onset PE, the level of receptors was 1.93 mg/L, which is 1.72 times higher than in the third trimester of uncomplicated pregnancy. The haptoglobin level in early-onset PE was 102.4 mg/dL vs. 65.5 mg/L in the second trimester of uncomplicated pregnancy, which is 1.56 times higher. In late-onset pregnancy, the haptoglobin level was 134.5 mg/dL vs. 46.3 mg/dL in the third trimester of uncomplicated pregnancy, which is 2.9 times higher. The difference in iron metabolism parameters in pregnant women with FGR vs. uncomplicated pregnancy peaked, with level of soluble transferrin receptors, which amounted to 2.09 mg/L and was 26.7 % higher than in PE without FGR most informative.

Conclusion. PЕ is associated with iron imbalance, characterized by maternal iron overload and relative fetal iron deficiency due to placental dysfunction. It cautions to widely use iron supplements and emphasizes the need for a personalized treatment approach. Thus, our findings contribute to our understanding multifaceted PE pathogenesis and revisiting both its diagnostic and prognostic markers, which may aid in risk stratification for early-onset and late-onset PE.

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