The differential effects of full-time and part-time work status on breastfeeding.
OBJECTIVES
Return to work is associated with diminished breastfeeding. Although more mothers breastfeed after returning to work compared to a decade ago, research has not documented the variations in breastfeeding initiation and duration based on full-time and part-time (less than 35h/week) work status. In this study, we clarify these differences.


METHODS
Longitudinal data from the Infant Feeding Practices Study II, collected between 2005 and 2007, for over 1400 mothers are used. In analyzing initiation, mother's work status was categorized by the expected number of hours she planned to work postpartum. In the duration model, work status was categorized based on the actual number of hours worked upon mother's return to employment after controlling for baby's age when she returned to work. Covariates in logistic and censored regressions included demographics, maternity leave, parity, past breastfeeding experience, hospital experience, and social support.


RESULTS
Compared with expecting not to work, expecting to work <35h/week was not associated with breastfeeding initiation while expecting to work full-time decreased breastfeeding initiation. Compared with breastfeeding mothers who did not work, returning to work within 12 weeks regardless of work status and returning to work after 12 weeks while working more than 34h/week were associated with significantly shorter breastfeeding duration.


CONCLUSION
Part-time work and increased amount of leave taken promote breastfeeding initiation and duration.