Late-onset hypertensive disorders of pregnancy and red blood cell distribution width during late pregnancy among Japanese primipara: A nested case-control study

Abstract

Background This study aimed to compare the red blood cell distribution width (RDW) between patients with late-onset hypertensive disorders of pregnancy (HDP) and healthy pregnant Japanese primiparas. Methods This nested case-control study was conducted at Ohta Nishinouchi Hospital in Fukushima, Japan, from 2014 to 2020. We included 110 patients with late-onset HDP and 110 propensity score-matched control participants with healthy pregnancies. Late-onset HDP was further categorized into gestational hypertension (n = 43) and preeclampsia (n = 67). The RDW was compared between the control and HDP groups during the first and third trimesters. Generalized linear mixed models (GLMMs) were used to examine changes in RDW during the two phases in the control and HDP groups. Results In the comparison between the control and HDP groups, no significant difference was noted in the median RDW during the first trimester (p = 0.569) or median RDW during the third trimester (p = 0.570). Comparing the gestational hypertension and preeclampsia groups, there was no significant difference in the RDW at the first (p = 0.179) and third trimesters (p = 0.828). The GLMMs showed significant phase changes in the RDW in both the control (p < 0.05) and HPD (p < 0.05) groups. Conclusions Although the RDW increased as the pregnancy progressed in the late-onset HDP group, the same changes were observed in the control group. RDW changes common to all groups may reflect maternal inflammatory responses that occur during pregnancy.