DISENTANGLING MATERNAL DECISIONS CONCERNING Breastfeeding and paid EMPLOYMENT

1. DISENTANGLING MATERNAL DECISIONS CONCERNINGBreastfeeding and paid EMPLOYMENT Bidisha Mandal, Washington State University Brian E. Roe, Ohio State University Sara B. Fein, Food & Drug Administration ASHEcon June 23, 2010

2. Motivation • Importance of breastfeeding in developed countries is increasingly emphasized • National U.S. health objectives call for exclusive breastfeeding for at least 6 months and breastfeeding duration for at least 12 months • More U.S. mothers of infants are participating in the workforce • More mothers of infants are combining market work and breastfeeding • Postpartum return to work is associated with lower rates of initiation and shorter duration of breastfeeding in the U.S. • Conflict between economic incentives from labor market and health benefits (to both mother and child) from breastfeeding

3. Objective • What is the decision process regarding work leave and breastfeeding durations? • What is the decision process regarding work effort and breastfeeding intensity?

4. Data – Infant Feeding Practices Study II • Conducted by the FDA in collaboration with the CDC from May 2005 to June 2007 • Longitudinal study of women from late pregnancy through their infant’s first year of life - 12 surveys (primarily mail) • 1 prenatal questionnaire • 1 telephone interview near the time of the infant’s birth • 1 neonatal questionnaire at infant age 1 month • 9 questionnaires sent about every 4 weeks during infant ages 2 to 7 months and then approximately every 7 weeks until infant age 12 months • 4902 qualified pregnant women completed the prenatal questionnaire

5. Sample • Not enough information if due date was more than 3 months away or did not complete neonatal questionnaire • 1885 cases deleted (3017 remaining) • Conditioning on pre-birth market work • 1506 cases deleted (1511 remaining) if no prenatal work activity • Prenatal work = working for pay at any time from the 3 months before pregnancy until last trimester; does not have to be full-time worker • 468 women did not initiate breastfeeding and/or worked pre-birth but did not intend to return to work • Excluded • 1049 remaining • Have full information (on all variables of interest) for only • N = 744 women for duration models • N = 648 women for month 3 intensity model • N = 586 women for month 6 intensity model

6. Selection Bias? • Breastfeeding initiation and work leave duration • Work leave duration is shorter for those who do not initiate (11.3 wks vs. 13.5 wks) • But, using Hausman endogeneity test, initiation is not endogenous to the determination of work leave duration • Intention to return to work and breastfeeding duration • Breastfeeding duration is shorter for those who return to work (25.3 wks vs. 31.4 wks) • Again, using Hausman endogeneity test, intention is not endogenous to the determination of breastfeeding duration Initiation Breastfeeding duration Intention Work leave duration

7. Models • Breastfeeding and work leave durations • Both activities are right censored • End of survey censoring or missing data censoring • Exclusive breastfeeding and work leave durations • Both activities are right censored • End of survey censoring or missing data censoring • Breastfeeding intensity and work effort at months 3 and 6 • Both activities are left censored • Observe intensity or effort only if participating in activity • 4 cases – both observed, only one observed, both unobserved

8. Variables of Interest • Dependent variables • Length of time that a woman breastfeeds her infant (25.3 wks) • Length of time that a woman exclusively breastfeeds her infant (7.8 wks) • Length of time before a woman returns to employment postpartum (13.5 wks) • Number of breastfeedings per day at infant age 3 months (4.7) • Number of breastfeedings per day at infant age 6 months (3.2) • Number of hours of market work per week at infant age 3 months (10-19 hrs/wk) • Number of hours of market work per week at infant age 6 months (20-29 hrs/wk) • Independent variables • Background – age, education, race, marital status, residence • Parity – number of other children and experience with breastfeeding • Birth and breastfeeding – if mother was breastfed, comfort, pregnancy complications, problem breastfeeding, attended breastfeeding class • Prenatal job characteristics – self-employed, part-time work, available work leave, supportive at work, satisfaction with work, contribution to family income, occupation type

9. Estimation Method • Full Information MLE • Log scale

10. Data Limitations • Sample is probably not reflective of the average characteristics of the U.S. population • Higher average education • Higher income • Return to same employer • Not known

11. Work Leave and Breastfeeding Durations • Decision process is recursive rather than fully simultaneous • Longer leave from work increases duration of breastfeeding • Every percent increase in work leave increases breastfeeding duration by half percent • Duration of breastfeeding is not a significant determinant of work leave • Significant covariates • Mother’s age, education and married status are positively related to duration of breastfeeding • Women in western and northeastern states of U.S. breastfeed longer • Women with one other child who was also breastfed breastfeed longer • Women with no work leave available return to work sooner • Women who are satisfied with their work return sooner • Women who have 1 or more children and who has not breastfed before take longer leaves ; women who have more than 1 child and has breastfed before take shorter leave

12. Exclusive Breastfeeding Duration • Decision process is again recursive rather than fully simultaneous • Every percent increase in work leave increases exclusive breastfeeding duration by 0.66 percent • Duration of exclusive breastfeeding is not a significant determinant of work leave • Additional significant covariates • Self-employed women exclusively breastfeed longer • Self-employed women take longer leave from work • Women whose contributions to household income is more than 50% exclusively breastfeed for shorter duration • Change in sign • Women with one other child who was also breastfed exclusively breastfeed for shorter duration (time constraints?) • Negative correlation between unobserved factors

13. Work Effort and Breastfeeding Intensity • Recursive process (both months 3 and 6) • Work effort constraints breastfeeding intensity but the reverse is not true • Every 5-10 hour/week increase in work is associated with 1 less breast-milk feeding per day • Common significant covariates in months 3 and 6 • Higher number of daily breastfeedings among higher educated women • Lower number of daily breastfeedings among women in southern states • Lower number of daily breastfeedings among women who are not comfortable with breastfeeding • No available leave is associated with less work effort • Higher contribution to family income is associated with higher work effort

14. Conclusions • Healthy People 2010 • Goal: 50% women breastfeeding at month 6, 25% at 1 year • 1990’s: 29% women breastfeeding at month 6, 16% at 1 year • Current: 43% women breastfeeding at month 6, 21% at 1 year • High degree of competition between breastfeeding and work • In terms of both duration and effort • Results indicate that employment decisions are made first • Longer work leave implies longer duration of breastfeeding and exclusive breastfeeding • More time spent at work means lesser number of breastfeedings • Working women probably face constraints at the workplace that are more rigid than those surrounding breastfeeding decisions • Similar results found in IFPS I (1992-1993) • Need for more workplace support