DISENTANGLING MATERNAL DECISIONS CONCERNING
BREASTFEEDING AND PAID EMPLOYMENT
Bidisha Mandal, Washington State University
Brian E. Roe, Ohio State University
Sara B. Fein, Food & Drug Administration
June 23, 2010 ASHEcon
Motivation1
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
Objective
What is the decision process regarding work leave and breastfeeding durations?
What is the decision process regarding work effort and breastfeeding intensity?
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Data – Infant Feeding Practices Study II3
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
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
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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
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Initiation
Intention
Breastfeeding duration
Work leave duration
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
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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
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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
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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
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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
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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
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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
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