Related Experiment Video
Updated: Aug 9, 2025

Modeling Encephalopathy of Prematurity Using Prenatal Hypoxia-ischemia with Intra-amniotic Lipopolysaccharide in Rats
Published on: November 20, 2015
Relationship between Platelet-to-Lymphocyte Ratio and Lymphocyte-to-Monocyte Ratio with Spontaneous Preterm Birth: A
Liang Peng1, Baodi Cao2, Fangpeng Hou3
1Department of Gynecology and Obstetrics, The Second People's Hospital of Jingdezhen, Jingdezhen, Jiangxi, China.
Insights
Platelet-to-lymphocyte ratio (PLR) is significantly elevated in spontaneous preterm birth cases, suggesting its potential as a diagnostic biomarker. Lymphocyte-to-monocyte ratio (LMR) showed no significant association with spontaneous preterm birth in this meta-analysis.
Area of Science:
- Obstetrics and Gynecology
- Inflammation Biomarkers
- Perinatal Medicine
Background:
- Spontaneous preterm birth (SPB) is a major obstetric complication with complex etiology and significant infant morbidity.
- Novel inflammation biomarkers, platelet-to-lymphocyte ratio (PLR) and lymphocyte-to-monocyte ratio (LMR), have been investigated for their association with SPB.
Approach:
- A systematic review and meta-analysis were conducted using data from multiple databases up to February 2022.
- Nine studies were included to evaluate differences in PLR and LMR between SPB patients and full-term controls.
- Statistical heterogeneity, publication bias, and sensitivity were assessed.
Key Points:
- Serum PLR was significantly higher in patients with SPB compared to full-term controls (SMD = 0.49, P = 0.007).
- No statistically significant difference in serum LMR was found between SPB patients and full-term controls (SMD = 0.35, P = 0.199).
- Publication bias and sensitivity analyses indicated robust findings.
Conclusions:
- PLR is strongly associated with spontaneous preterm birth, indicating potential clinical utility.
- LMR does not appear to be significantly associated with spontaneous preterm birth.
- Further research is needed to elucidate the mechanisms behind elevated PLR in SPB and identify other contributing factors.
Background:
Spontaneous preterm birth is one of the most common pregnancy complications in obstetric clinical practice, and its etiology is complex. The problems of low survival and high morbidity rates of premature infants need to be solved urgently. The platelet-to-lymphocyte ratio (PLR) and lymphocyte-to-monocyte ratio (LMR) are two novel biomarkers of inflammation, and several studies have linked PLR and LMR to spontaneous preterm birth. These systematic review and meta-analysis are aimed at analyzing the relationship between PLR and LMR in patients with spontaneous preterm birth to provide new ideas for the early prevention and treatment of spontaneous preterm births.
Methods:
Cochrane Library, EMBASE, PubMed, and China National Knowledge Infrastructure databases were inspected to gather PLR and LMR in patients with spontaneous preterm birth, all from the database to February 2022. Interstudy heterogeneity was evaluated using Cochran's Q test and I 2 statistic. Differences in PLR and LMR between patients with spontaneous preterm birth and full-term controls were evaluated by computing standardized mean differences and 95% confidence intervals. Publication bias and sensitivity analyses were also performed.
Results:
Nine studies were included in the meta-analysis based on the inclusion and exclusion criteria. The meta-analysis showed that serum PLR values were remarkably larger for patients with spontaneous preterm birth than for full-term controls (SMD = 0.49, 95% CI: 0.13 to 0.84, P = 0.007), whereas the difference between serum LMR in patients with spontaneous preterm birth and full-term controls was not statistically significant (SMD: 0.35, 95% CI: -0.18, 0.88, P = 0.199). The results of Begg's and Egger's tests revealed that the publication bias of the meta-analysis was not significant. The outcomes of the sensitivity analysis showed that the individual studies did not influence the meta-analysis results.
Conclusions:
Current evidence shows that PLR is strongly associated with spontaneous preterm birth, whereas LMR is not. PLR has a certain clinical value in diagnosing and treating spontaneous preterm births, and our research will provide strong theoretical support for clinical work. In the future, it will be necessary to further explore the reasons for the increased PLR in the serum of patients with spontaneous preterm birth and other mechanisms inducing spontaneous preterm birth.

