Immunoglobulin G Levels in Yemeni Preterm Newborns: Infant Factors Predominate

ABSTRACT Background IgG levels in preterm infants play a crucial role in response to infection and inflammation. Infectious disease burden in the low‐income countries, such as Yemen, exacerbates the problem. The preterm infant's IgG sources are either maternal or fetal immune system. The aim of this study was to determine the IgG level in preterm Yemeni infants and to investigate the relative contribution of both maternal and infant factors to IgG elevation. Subjects and Methods This cross‐sectional study was conducted on 107 preterm newborn babies (< 37 weeks of gestation) in the Ibb governorate, Yemen. The babies' and maternal data were collected in the full questionnaire. Approximately 4 mL of blood sample was collected and analyzed for complete blood count and immunoglobulin G level determination. Results Most preterm newborns were male (69.2%). The mean IgG level in preterm infants was 1160.7 ± 350.8 mg/dL. Twenty‐one preterm babies had IgG levels above normal (1661.5 ± 213.9 mg/dL). A higher IgG level was associated with babies' problems: fetal stage problems (OR = 3.9, 95% CI = 1.18–12.87, p = 0.047), home birth (OR = 5.70 at 95% CI = 1.92–16.90, p = 0.002), and postnatal infections (OR = 3.03, 95% CI = 1.13–8.13, p = 0.044). However, a statistically significant association of IgG levels was with maternal pregnancy problems (hypertension, bleeding, and infections) with an odds ratio of 0.196, 95% CI = 0.43–0.90, p = 0.044. The preterm baby's IgG was positively correlated with age ( r = 0.375, p < 0.0001), weight ( r = 0.743, p < 0.0001), and days of hospitalization ( r = 0.305, p = 0.002). Conclusion In Yemeni preterm neonates, IgG is generally elevated due to infections. This elevation is primarily driven by infant‐specific factors rather than maternal factors. Further studies are needed to explore these factors profoundly with a large sample size.