Placental DNA methylation, maternal oxidative stress, and infant's birth weight

Aims: DNA methylation is among the best-characterized epigenetic mechanisms that play a regulatory role in genome programming and imprinting during embryogenesis. Vital DNA methylation patterns may be beneficial to long-term health. In the study presented here, we investigated the association between placental DNA methylation and adverse birth outcome and estimated whether there was a relation between maternal oxidative stress during second trimester and DNA methylation status.

Material and Methodology: We investigated 108 pregnant women who visited Ewha Womans University Hospital. Their serum homocysteine and 8-hydroxy-2'deoxyguanosine (8-OHdG) concentrations were measured during the 25-28 weeks of gestation of their pregnancy. Placental DNA methylation status was estimated using immunohistochemistry method. A general linear model analysis was used to estimate the relationship between DNA methylation levels and infant's birth weight controlling for maternal age, BMI, and pregnancy weight gains.

Results: We found that increasing concentrations of homocysteine and 8-OhdG were associated with reduced placental DNA methylation. There was a dose-response relation between placenta DNA methylation and Infant's birth weight. Infant's birth weight were significantly higher in women who had higher DNA methylation (>median) in others (p<0.05).

Conclusion: These findings suggest that placental DNA methylation affect adverse pregnancy outcome and it was associated with maternal oxidative stress levels during pregnancy. “These work was supported by Korea Research Foundation Grant (KRT-2005-204-E00049).”