Monocyte to HDL-C Ratio as an Early Prognostic Marker of Pregnancy Complications: An Observational Study

Abstract

Background: Pregnancy is accompanied by substantial physiological, metabolic, inflammatory, and cardiovascular adaptations that are essential for normal maternal and fetal development. In some women, these adaptations are associated with pregnancy-related complications, including hypertensive disorders of pregnancy, preeclampsia, gestational diabetes mellitus (GDM), intrauterine growth restriction (IUGR), and preterm delivery, which may adversely affect maternal and perinatal outcomes. Increasing attention has been directed toward readily available biomarkers that can reflect the inflammatory and metabolic alterations occurring early in pregnancy. The monocyte to high-density lipoprotein cholesterol ratio (MHR) integrates two biologically relevant parameters: monocytes, which contribute to inflammatory processes, and HDL-C, which possesses anti-inflammatory, antioxidant, and endothelial-protective properties. The present study was undertaken to evaluate whether MHR measured during early pregnancy could serve as an accessible prognostic marker for subsequent pregnancy complications. Methods: This observational study was conducted in the Department of Obstetrics and Gynaecology at SRM Medical College Hospital and Research Centre. Participant recruitment was carried out from July 2025 to March 2026. A total of 150 pregnant women were recruited during the first trimester after obtaining informed written consent. For consistency with the study eligibility criteria, pregnant women aged 18–40 years with singleton pregnancies were considered eligible for enrolment. Women with multiple pregnancies, pre-existing diabetes mellitus or chronic hypertension, recent use of lipid-lowering, anti-inflammatory or immunosuppressive medications, acute infection or inflammatory illness at the time of sampling, smoking or substance abuse during pregnancy, and those with incomplete antenatal follow-up were excluded. Early-pregnancy venous blood samples were assessed for hematological parameters, including absolute monocyte count, and biochemical parameters including HDL-C and other lipid-profile components. The MHR was calculated by dividing the absolute monocyte count by the serum HDL-C concentration. Following enrolment and baseline assessment, participants were followed prospectively until delivery, and the development of gestational hypertension or preeclampsia, GDM, IUGR, preterm delivery, and other clinically documented maternal or fetal complications was recorded. Statistical analysis was performed using appropriate descriptive and inferential statistical methods, with statistical significance considered at a p-value of <0.05. Results: The study was designed to determine the relationship between early-pregnancy MHR and the subsequent occurrence of pregnancy complications. The principal analysis will compare early-pregnancy MHR values between women who develop pregnancy complications and those who remain without documented complications during follow-up. The predictive performance of MHR will additionally be assessed in relation to individual complications, particularly hypertensive disorders of pregnancy, preeclampsia, GDM, IUGR, and preterm delivery. The study will also evaluate whether an elevated early-pregnancy MHR is associated with adverse maternal and fetal outcomes and whether the marker demonstrates potential utility as an early, routinely measurable indicator of increased pregnancy risk. Conclusion: The study evaluates the potential role of the monocyte to HDL-C ratio as an early and accessible biomarker for identifying pregnant women at increased risk of subsequent pregnancy complications. Because MHR incorporates an inflammatory cellular component and an anti-inflammatory lipid component, its assessment during early pregnancy may provide clinically relevant information regarding the inflammatory and metabolic milieu preceding adverse pregnancy outcomes. If a significant association is demonstrated, MHR may have potential as a simple, cost-effective adjunct to conventional antenatal risk assessment. Further evaluation in larger prospective cohorts would be required to establish its diagnostic and prognostic performance and determine its applicability in routine obstetric practice.