Inflammatory markers and their association with preeclampsia among pregnant women: A systematic review and meta-analysis

The goal of this review was to investigate the levels of pro-inflammatory markers such as Tumour necrosis factor-α (TNF-α) Interlukin-6 (IL-6), C-reactive protein (CRP), Transforming growth factor-β1 (TGF-β1) and ferritin in pre-eclamptic and normotensive pregnant women. Using PubMed, ProQuest and Google Scholar databases, a literature search was carried out and case-control studies showing associations between inflammatory markers and preeclampsia in pregnancy published between 2010 and 2023 were included. The risk of bias was assessed by using the Newcastle Ottawa quality assessment scale. A random effect meta-analysis was performed and pooled difference in means with 95 % CI were reported. All statistical analyses were performed using R software. Out of 660 articles, 25 articles were included in the systematic review. The differences in means for TGF-β1, CRP, ferritin and TNF-α levels between the preeclamptic women and normotensive women were 2.37 pg/mL [95 % CI: −1.66,6.39], 5.62 mg/L [95 % CI: −4.11,15.36], 32.93 ng/mL [95 % CI: −7.66,58.19] and 13.67 pg/mL [95 % CI: 4.20,23.14] respectively which showed moderate increase. The pooled differences in means for hs-CRP and IL-6 levels between the preeclamptic and normotensive women were 3.20 mg/L [95 % CI: 0.27,6.12] and 17.64 pg/mL [95 % CI: −8.36,43.64] respectively which showed significant increase. Sub-group analysis showed significant differences for CRP, ferritin and TNF-α levels across ethnicities. Meta-analysis demonstrates an increase in the maternal circulating levels of inflammatory markers such as hs-CRP, IL-6 and showed moderate increase in TGF-β1, CRP, ferritin, TNF-α markers among women affected by preeclampsia compared to those with normotensive pregnancies.