P3.A014: Maternal Milk is associated with Lower Maternal Stress at NICU Discharge in Preterm Infants

Background: Mothers of preterm infants experience an increased incidence of perinatal mood and anxiety disorders compared to those of healthy term infants. Maternal emotional distress has a negative effect on maternal-infant bonding and neonatal brain development. Although the benefits of maternal milk for preterm infants are well-established, the implications for maternal mental health are not well-explored. The Parental Stressor Scale: Neonatal Intensive Care Unit (PSS:NICU) is a validated tool to assess the impact of the NICU environment on perceived parental stress. We sought to investigate the relationship between maternal milk provision to hospitalized preterm infants and levels of perceived maternal stress.

Methods: Mother-infant dyads of hospitalized preterm infants (birth gestational age < 37 weeks) were enrolled as part of a prospective, observational study in an urban level IV NICU. Mothers completed the PSS:NICU questionnaire upon NICU admission and then every 4-6 weeks throughout infant’s hospitalization. Infant feeding type (human milk versus formula) was recorded from hospital admission through NICU discharge or term-equivalent age, whichever was achieved first. Statistical analysis (IBM SPSS Statistics) was performed using paired t-test, chi-square analysis, and analysis of variance.

Results: Eighty-four mother-infant dyads were followed throughout the NICU hospitalization. Seventy-one infants (85%) received maternal milk during NICU hospitalization, however only 36 infants (43%) were discharged receiving maternal milk compared to 48 (57%) receiving formula. Infants discharged on formula were more likely to be born at a younger gestational age and to Black or African American mothers, with no significant differences in maternal age or parity between groups (Table 1). Average maternal stress scores significantly decreased from hospital admission to discharge (from 38 +/-14 to 27 +/-19, p < 0.001), with a more profound decrease in infants receiving maternal milk compared to formula (Figure 1a). At NICU discharge, mothers of maternal milk-fed infant demonstrated significantly lower stress scores that those receiving formula (Figure 1b).

Conclusion: These findings suggest an important relationship between maternal milk provision and stress levels at NICU discharge. Mothers providing human milk at hospital discharge demonstrated a greater decrease in maternal stress scores throughout NICU hospitalization and lower stress scores at hospital discharge than formula, suggesting that the maternal ability to provide milk may serve as a protective factor for maternal mental health. These data emphasize the importance of efforts to sustain maternal milk supply throughout the NICU hospitalization for maternal well-being in addition to the known benefits for preterm infants.