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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Estimation Method

Full Information MLE

Log scale

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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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