Association Between Maternal C-Reactive Protein (CRP) Levels and Adverse Neonatal Outcomes: A Systematic Review and...

Area of Science:

• Obstetrics and Gynecology
• Neonatology
• Immunology

Background:

• C-reactive protein (CRP) is a key biomarker for systemic inflammation.
• Maternal CRP levels have been linked to adverse pregnancy and neonatal outcomes, but the precise relationship requires further clarification.
• Systemic inflammation's role in pregnancy complications is an area of active research.

Purpose of the Study:

• To systematically review and meta-analyze observational studies investigating the association between maternal C-reactive protein (CRP) levels and neonatal outcomes.
• To quantify the relationship between elevated maternal CRP and specific adverse neonatal outcomes, including preterm birth, low birth weight, small for gestational age, and stillbirth.

Main Methods:

• A comprehensive literature search was conducted across major databases (PubMed, Scopus, Web of Science, Cochrane Library) up to July 2025.
• Included 42 observational studies with data from 18,393 pregnant women, analyzing maternal CRP levels against neonatal outcomes.
• Random-effects models were employed to calculate pooled effect sizes (SMD, OR) with 95% confidence intervals (CI), assessing heterogeneity with the I² statistic.

Main Results:

• Maternal CRP levels were significantly higher in cases of adverse pregnancy outcomes compared to controls (SMD = 0.39).
• Elevated maternal CRP showed a strong association with increased odds of preterm birth (OR = 3.81) and low birth weight (OR = 2.34).
• No significant associations were found between maternal CRP and small for gestational age (OR = 1.14) or stillbirth (OR = 1.89).

Conclusions:

• Maternal C-reactive protein (CRP) is significantly associated with an elevated risk of preterm birth and low birth weight.
• The findings underscore the role of systemic inflammation in adverse neonatal outcomes.
• Further prospective research is needed to elucidate causal pathways and evaluate CRP's clinical utility in pregnancy risk assessment.