AIM

Sex-based differences in response to adverse prenatal environments and infant outcomes have been observed, yet the underlying mechanisms for this are unclear. The placental epigenome may be a driver of these differences.

METHODS

Placental DNA methylation was assessed at more than 480,000 CpG sites from male and female infants enrolled in the extremely low gestational age newborns cohort (ELGAN) and validated in a separate US-based cohort. The impact of gestational age on placental DNA methylation was further examined using the New Hampshire Birth Cohort Study for a total of n = 467 placentas.

RESULTS

A total of n = 2745 CpG sites, representing n = 587 genes, were identified as differentially methylated (p < 1 × 10). The majority (n = 582 or 99%) of these were conserved among the New Hampshire Birth Cohort. The identified genes encode proteins related to immune function, growth/transcription factor signaling and transport across cell membranes.

CONCLUSION

These data highlight sex-dependent epigenetic patterning in the placenta and provide insight into differences in infant outcomes and responses to the perinatal environment.