The purpose of this study is to learn how early language exposure may be related to changes in DNA in parents and their premature infants. While a person's genetic code is determined at the time of conception, the way that some genes are expressed in the body can be changed even after an individual is born. These changes are called epigenetic changes. In this study, the investigators want to learn about the epigenetic changes that happen after a premature baby is born and whether a parent's interaction with their baby can influence these epigenetic changes. The investigators will look at epigenetic changes by collecting saliva samples from parents and their preterm babies, here defined as babies born at <33 weeks gestation. Specifically, the investigators will be looking at salivary levels of DNA methylation of the oxytocin receptor gene (OXTRm). The investigators will track changes in OXTRm levels over time in parents and their babies and see if these levels change in relation to how much time parents spend with their babies and how much time they spend reading to their babies. The investigators will ask mothers and, if desired, their partners to read to their babies for at least 15 minutes per week. The investigators will ask them to track time spent with the baby and reading time on a log, and will also measure word count with a commercially-available LENA device. The investigators will use logistic regression analysis to identify the independent association between OXTR DNA methylation and time spent with parent(s) and word count.

Student's t-test and Pearson's chi-square tests will be used to compare continuous and categorical variables, respectively. Logistic regression analysis will used to identify the independent association between OXTR DNA methylation and time spent with parent(s) and word count. Variables with p≤0.20 in the univariate analysis will be entered into a stepwise logistic multivariate regression model. Odds ratios with 95% confidence intervals will be calculated. p value of less than 0.05 will be considered statistically significant.

A protocol modification was submitted to and approved by the University of Virginia IRB due to slower than expected participant enrollment. The protocol was modified such that:

• Enrollment of <33 week instead of <32 week infants was permitted
• Enrollment was permitted through the first 2 weeks after birth instead of through the first 1 week after birth

Inclusion Criteria:

• Infants <33 week gestational age at birth
• Mother must be able to visit at least once per week
• Mother or primary caregiver must participate; father or secondary caregiver may participate as well
• Mother must commit to minimum of 15 minutes reading at least once per week

Exclusion Criteria:

• Infant with life-limiting conditions
• Mother is non-English speaking
• Illiteracy of mother