Mariana Amorim,Erica Hobby,Anna Zamora-Kapoor,Katherine A. Perham-Hester,Sarah K. Cowan
The heterogeneous associations of universal cash-payouts with breastfeeding initiation and continuation
Income support,Breastfeeding,Disparities,Alaska
Existing health literature documents the benefits of breastfeeding for the first six months of life. Prior research on barriers to breastfeeding has focused on the role of hospital initiatives, return to work, and individual mothers' characteristics. This study uses data from Alaska's Pregnancy Risk Assessment Monitoring System and the Alaska Permanent Fund Dividend, to investigate whether universal income support shapes mothers' breastfeeding behaviors. We find that payouts are associated with increases in breastfeeding initiation and short-term continuation (three months) among a sample of urban Alaskan mothers. These associations differ across mothers' socioeconomic and demographic characteristics (i.e., education, economic status, race, marital status). We contend that this type of income intervention may complement existing efforts to promote breastfeeding by removing financial barriers to breastfeeding.
The heterogeneous associations of universal cash-payouts with breastfeeding initiation and continuation

Existing health literature documents the benefits of breastfeeding for the first six months of life. Prior research on barriers to breastfeeding has focused on the role of hospital initiatives, return to work, and individual mothers' characteristics. This study uses data from Alaska's Pregnancy Risk Assessment Monitoring System and the Alaska Permanent Fund Dividend, to investigate whether universal income support shapes mothers' breastfeeding behaviors. We find that payouts are associated with increases in breastfeeding initiation and short-term continuation (three months) among a sample of urban Alaskan mothers. These associations differ across mothers' socioeconomic and demographic characteristics (i.e., education, economic status, race, marital status). We contend that this type of income intervention may complement existing efforts to promote breastfeeding by removing financial barriers to breastfeeding.

Although most US mothers initiate breastfeeding, only one in four continue to breastfeed exclusively for the six months recommended by the American Academy of Pediatrics (Perrine et al., 2012). Experiences of breastfeeding are highly stratified by race, education, and income, with breastfeeding mothers more likely to be Non-Hispanic White, to have professional occupations or be out of the labor force, and to have higher levels of education and income compared to non-breastfeeding mothers (e.g., Cisewski & McCann, 2018; Haider et al., 2003; Louis-Jacques et al., 2017). These disparities have motivated policies that promote exclusive breastfeeding among at-risk populations (US Department of Health and Human Services n. d.). Although prior studies investigate the role of mothers’ individual characteristics (Chang et al., 2020; Thomson et al., 2017) and work or leave conditions (Dagher et al., 2016) on breastfeeding initiation and continuation, little research addresses whether distal interventions, like universal income support, may influence breastfeeding (Hamad & Rehkopf, 2015). Our study contributes to the literatures on breastfeeding, social determinants of health, and social policies by investigating the heterogeneous role of universal and unconditional cash transfers on breastfeeding using the case of the Alaska Permanent Fund Dividend (hereafter Alaska Dividend). Starting in 1982, equal cash payments have been distributed in October of each year to all Alaskans (who resided or were born in the state in the previous calendar year) regardless of socioeconomic and demographic characteristics such as age, income, and work status. Using data from Alaska's Pregnancy Risk Assessment Monitoring System (PRAMS), we exploit (i) annual variation in the generosity of the Dividend and (ii) the seasonal nature of births and payouts to estimate if postpartum Alaskans' likelihood of breastfeeding changes when payouts increase, and the timing of breastfeeding initiation or continuation is aligned with payouts' disbursement in October. Our findings suggest that universal income support may complement existing efforts to promote breastfeeding by removing financial barriers faced by mothers.

Studies indicate that breastfeeding strengthens infants' immune systems (Victora et al., 2016), reduces the risk of post-neonatal mortality (Chen & Rogan, 2004), and prevents sudden infant death syndrome (Thomson et al., 2017), infections (Victora et al., 2016), asthma (El-Heneidy et al., 2018), and childhood obesity (Isong et al., 2018). Extant research also documents physical health benefits for mothers who breastfeed, including decreased postpartum bleeding (Kennedy et al., 1996) and decreased risk of breast cancer (Jernström et al., 2004). Although most evidence on the benefits of breastfeeding for children's and mothers' health is based on observational studies, a large experimental study (Kramer et al., 2001) also finds that breastfeeding offers health benefits to children (i.e., improves digestion in the first year and reduces the incidence of rashes and ear infections) and mothers (i.e., lowers the risk of breast cancer). As a result of this international literature, exclusive breastfeeding during infancy is endorsed by leading medical associations (American Academy of Pediatrics, 2012; World Health Organization, 2020).

Most US mothers are committed to breastfeed, and consider breastfeeding an essential experience of successful motherhood and an important venue to invest in children's health (Dykes, 2005; Perrine et al., 2012). Still, 75% of US children are not breastfeed for the first six months of life (Perrine et al., 2012). Previously recorded individual-level barriers to breastfeeding can be classified into the following groups: 1) physical challenges: pain, discomfort, and inadequate milk production (Chang et al., 2020; Li, Fein, et al., 2008); 2) health literacy: limited access to information promoting breastfeeding (Goodman et al., 2016; Thomson et al., 2017); 3) cultural factors: lack of cultural acceptance, language barriers, and acculturation (Bigman et al., 2018; Linares et al., 2019); and 4) lifestyle choices: preference to bottle-feed and personal habits such as smoking or alcohol consumption (Logan et al., 2016; Napierala et al., 2016). Studies also investigated the role of structural barriers to breastfeeding, such as work conditions and access to maternity leave. Although evidence on the impact of work plans on breastfeeding initiation is less consistent (see Murtagh and Moulton 2010), return to work – and in particular full-time work - has been consistently linked to the timing of breastfeeding cessation (Dagher et al., 2016; Gatrell et al., 2007; Guendelman et al., 2009; Kimbro, 2006; Roe et al., 1999) due to mothers' lack of time or institutional support to breastfeed (Dagher et al., 2016; Gatrell, 2007). Financial strains also represent important structural barriers to breastfeeding by increasing mothers’ experiences of stress, worsening mental health, and/or decreasing social support (Buck et al., 2018; Dozier et al., 2012; Li, Fein, et al., 2008). Importantly, financial and work circumstances may have compounding consequences (Kimbro, 2006; Guttman & Zimmerman, 2000). Because 1) women find it difficult to reconcile work and breastfeeding demands (Kimbro, 2006; Roe et al., 1999) and 2) the decision to breastfeed for long periods has been linked to both reductions in labor supply and loss of earnings (Rippeyoung & Noonan, 2012), mothers’ financial circumstances may play an important role in work-related decisions. Namely, whereas financially advantaged mothers may be able to work part-time or to opt out of the labor force to solve work-family conflicts (Stone 2007), economically disadvantaged mothers may need to shorten breastfeeding duration and return to work due to financial needs (Hawkins et al., 2007). Encouragingly, evidence suggests that removing some of the financial barriers to breastfeeding through paid leave policies increases breastfeeding rates among employed women (Hamad et al., 2019; Hawkins et al., 2007).

Few studies investigate the effects of income support on breastfeeding. An exception, Hamad and Rehkopf (2015) documented the relationship between payout sizes from the Earned Income Tax Credit (EITC) and breastfeeding initiation. They found that increases in EITC payouts are associated with marginal increases in the likelihood of initiating breastfeeding (β = 0.042 per $1000 [95% CI−0.0055, 0.089]). Recently, Sen et al. (2020) studied the impacts on breastfeeding initiation of a large conditional cash-transfer program in India (Janani Suraksa Yojana, JSY), which provides monetary incentives to poor mothers delivering in health facilities. They found that receiving JSY benefits significantly increases mothers’ chances of breastfeeding within 1 h of birth by 7.3%. Notably, both Hamad and Rehkopf (2015) and Sen (2020) investigated the consequences of conditional cash-assistance among specific subgroups of low-income mothers. It is possible, however, that imposing conditions on cash-assistance mitigates the benefits of such payouts on breastfeeding. For instance, Haider et al. (2003) found that US states that link stringent work requirements to temporary financial assistance reduce rates of breastfeeding six months after birth by 9% for all new mothers and by twice as much among lower-income mothers. Haider and colleagues’ (2015) findings draw attention to the potential benefits of unconditional cash transfers, or transfers that have no conditions attached. Universal and unconditional income support, such as the Alaska Dividend, has recently come to the center of policy debates in the US and the world, but their implications for maternal and child health are not well understood. Our study addresses this gap using the case of the Alaska Dividend.

The Alaska Dividend is an annual, universal, and unconditional cash-transfer established since 1982. The Dividend has unique features when compared to other cash-transfer programs: (i) it is distributed on an annual basis in the beginning of October; (ii) it is distributed to all individuals who resided or were born in Alaska in the previous calendar year; (iii) it has no age, income, employment, or family composition requirements; and (iv) it disburses equal payouts to all individual beneficiaries each year, regardless of socioeconomic characteristics. Notably, the size of individual payouts, which, until 2015, were calculated through a well-advertised formula (Erickson & Groh, 2012; Kueng, 2018), varies from year to year. Fig. 1 presents the individual payments and take-up rates for years included in this study (1996–2015). Breastfeeding literature suggests that universal income support may promote breastfeeding through two mechanisms: (i) less exposure to stress from financial hardships; or (ii) ability to reduce labor supply either through part-time work or longer work leaves (Fein 1998; Li, Fein, et al., 2008; Lindberg 1996; Ryan et al., 2006). Previous work on the Alaska Dividend finds indeed that the program (i) reduces poverty and financial hardship in Alaska (Berman, 2018) and (ii) allows mothers with young children – in particular, low-income mothers - to reduce hours of work in the short-term (Bibler et al., 2019). In this study, we test whether Dividend receipt is in fact associated to breastfeeding initiation and continuation, and how this association varies by mothers’ socioeconomic and demographic characteristics.

We utilize 1996–2015 data from the Alaska's Pregnancy Risk Assessment Monitoring System (PRAMS) to measure health behaviors and outcomes for mothers of newborns before, during, and after pregnancy. We exclude the more recent years of the PRAMS survey (2016-present) because of changes that occurred in the determination of payment sizes after 2015, which deemed payouts smaller, less predictable, and overall, not comparable with the longer period used in the study. PRAMS surveys are collected by the Centers for Disease Control and Prevention (CDC) from a stratified sample of postpartum women who are interviewed between 2 and 9 months after they gave birth. Alaska PRAMS oversamples Alaska Native mothers and those whose newborns were low birthweight. Mothers' responses are linked to information obtained from children's birth certificate. PRAMS does not ask about the gender of the respondent; in this manuscript, we alternate between feminine and gender-neutral descriptors.

In the main analyses, we restrict our sample to postpartum Alaskans who live in urban areas. We do so for three reasons: (1) This restriction improves generalizability of our results to Americans living outside of Alaska since rural areas in Alaska are much more remote than rural areas in the rest of the US, being characterized by a mix of subsistence and small formal economies (Goldsmith, 2012); (2) Current explanations for urban-rural differences in breastfeeding rely not only on population compositions but also on overall access to resources (Flower et al., 2008; Jones et al., 2009), suggesting interactive associations that would not be addressed through the simple inclusion of a control variable for geography; And (3) this sample restriction eliminates a potentially important confounder: public health investments, which could be correlated to Dividend amounts. Most urban residents in Alaska live in Anchorage, an area that, in contrast to the rest of the state, has not received any meaningful public health investments expanding mothers’ access to healthcare during the studied period (Borland et al., 2015). The 1996–2015 PRAMS data contain information on 17,816 postpartum women who were urban Alaska residents. Urban was defined as a resident of Anchorage, Fairbanks, Juneau, Ketchikan, or the Matanuska-Susitna Borough. Sitka residence was included for birth years 1996–2011. We exclude 6.1% of observations (N = 1095) that did not provide information on breastfeeding initiation or continuation until the infant was four weeks old, 280 observations for whom we could not generate a household size, and 6% of mothers who did not report their race. Our final sample is composed of 15,455 postpartum mothers. We use chained equations (N = 10) to impute information for 1345 mothers who had missing information on other key covariates, none of which were missing for over 3% of our sample.

We rely on one measure of breastfeeding initiation: whether respondents ever breastfed. We consider all mothers who report any length of time breastfeeding as initiators. We use two measures of breastfeeding continuation: (i) whether respondents breastfed for four or more weeks after birth; and (ii) whether respondents breastfed for three or more months after birth. Because respondents complete the PRAMS survey between two and nine months after the infant's birth, models investigating the third measure (breastfeeding at three or more months) are restricted to respondents with infants 90 days or older at the time of the questionnaire (n = 11,613).

The Alaska Dividend refers to equal individual cash payments that are distributed in October of each year to all Alaskans who resided or were born in the state in the previous calendar year, regardless of socioeconomic and demographic characteristics such as age, income, and work status. Following previous studies (Amorim, 2022; Cowan & Douds, 2022; Hsieh, 2003; Kueng, 2018), we use the total payout received by a family rather than the payout received by an individual as our independent variable of interest. The family payout was imputed by multiplying the annual individual payout (which varied from year to year, see Fig. 1) by household size. To determine household size, we added the respondent to their spouse (marital status information is collected from the child's birth certificate) and to the number of previous live births reported. The number of previous live births is measured in a categorical variable linked from the birth certificate: 1, 2, 3–5, and 6+. For respondents who reported 3–5, we assigned the average of 4. For those who reported 6+ previous births, we assigned the household 6 children. We measured the Dividend payout received by a family in hundreds of dollars and adjusted the final amount to 2015 dollars using the Bureau of Labor Statistics' Consumer Price Index West Region Data Tables. Finally, we assigned the payout to the six months preceding and following the disbursement (October), allowing for both anticipatory and spillover effects. For example, the payout from October 2010 (t) is assigned to respondents with births between the months of April 2010 (t-6) and March 2011 (t+6).

First, maternal educational attainment is categorized as high school degree or less (12 years of education or less), some college (13–15 years of education), or college degree or more (16 years or more of education). Second, because PRAMS did not collect measures of income consistently across years, and its income data has a high proportion of missing values (Shulman 2018), we use a binary variable that indicates whether respondents paid for prenatal healthcare using Medicaid (self-reported) as a proxy for income. Third, respondents are classified according to their marital status (married, not married). Finally, mothers are classified according to three distinct racial identities: White, American Indian/Alaska Native (AI/AN), and “Other race.” PRAMS oversamples AI/AN mothers, which allows us to investigate this group separately. Because the proportion of Asian, Black, and Native Hawaiian and Pacific Islander mothers in our sample is very small, we cluster these groups in the “Other race” category. Information on Hispanic ethnicity is missing for a large portion of the sample and thus not included in the main analyses.

Multivariate analyses control for the moderators described above and for the following socio-demographic characteristics: age (≤19, 20–24, 25–29, 30–34,35+), parity (1, 2, 3, ≥4), obesity status, and whether respondent received prenatal care in the first trimester of pregnancy, received assistance through the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC), experienced difficulty paying bills in the year prior to childbirth, lost a job or had a partner who lost a job in the 12 months prior to childbirth, smoked during third trimester, drank alcohol during the last three months of pregnancy, and experienced intimate partner violence before or during pregnancy. Moreover, models control for annual US trends in breastfeeding initiation (National Immunization Survey; Ross Mothers’ Survey). Table 1 reports the characteristics of our sample. About 92% of mothers ever breastfed, 81% breastfed at four weeks, and 64% breastfed at three months. About 74% identify as White, 13% identify as AI/AN, and 13% identify as another race. Over 70% were married, 24% had a college degree, and about 40% were having their first birth. About 35% of mothers in our sample used Medicaid during pregnancy, 44% received WIC, 22% had difficulties paying bills and 16% experienced a job loss (of self or partner) in the 12 months prior to birth. Eighty percent of mothers received prenatal care during the first trimester of their pregnancies, 22% were obese, and 13% smoked during the last three months of their pregnancies. The average total family Dividend was about $5185 (2015 dollars).

We conceptualize the Dividend payments as repeated natural experiments. The repeated nature of the treatment suggests other states may not be suitable counterfactuals for continually treated Alaskans (see also Cowan & Douds, 2022). Thus, instead of comparing breastfeeding behaviors of Alaskans and non-Alaskans, we exploit the seasonal nature of births and payouts to investigate if postpartum Alaskans' likelihood of breastfeeding increases when the timing of breastfeeding initiation or continuation is aligned with the Dividend's disbursement in October. Notably, our models identify changes in the likelihood of breastfeeding that are associated not only with the timing of Dividend receipt but also with changes in the annual payout sizes. Incorporating payout sizes to our models is important because the timing of payout disbursement may not be independent from any potential seasonality in breastfeeding or work if, for example, mothers are more likely to breastfeed during the cold season and/or less likely to work during winter. There is, however, no evidence or logic linking work or breastfeeding seasonality to variation in the size of payouts (see also Cowan & Douds, 2022; Erickson & Groh, 2012; Goldsmith, 2012). We measure changes in breastfeeding using logistic models as described below:where Yit is the log-likelihood that postpartum mother i will engage in breastfeeding initiation or continuation in Dividend year t (from April to March). Ti denotes the estimated family Dividend received by postpartum mother i in year t (in hundreds of dollars), and Miθ represents a series of indicators for the month in which postpartum mother i gave birth to focal newborn, with April omitted as the reference category. xi is the 1 × k regressor vector (where k is the number of controls described above), and λ is the k × 1 vector of parameters. εiθt are changes in breastfeeding behavior not explained by variables included in the model. Additionally, we conducted analyses interacting Tit and Miθ to each moderator (i.e., educational attainment, Medicaid use, race identity, marital status). All analyses are weighted using the PRAMS survey weights and the svy commands in Stata. After presenting main results, we test the sensitivity of our results to the inclusion of alternative measures of the Dividend, control variables, and moderators, and to alternative sample restrictions. We use average marginal effects (AMEs) to summarize associations between payouts and breastfeeding. AMEs allow us to account for multiple linked coefficients (main and interaction terms, βθ and δθ) and to express results as changes in predicted probabilities (Mize, 2019). Notably, AMEs are not causal estimates: they report on the average change in the probability of breastfeeding in each month associated with a $100 increase in annual payouts.

Fig. 2 documents the average marginal effects (AMEs) and 95% confidence intervals of receiving an additional $100 in October (month 0) on the predicted probabilities of (i) ever breastfeeding, (ii) breastfeeding at four weeks, and (iii) breastfeeding at three or more months for children born x months before (-x) or after (+x) disbursement. A table including individual coefficients for each model is included in Online Appendix A. This Appendix, however, must be interpreted with caution since best practices recommend that interactive associations in nonlinear models be tested in the natural metric of the variable (i.e., as predicted probabilities; see Mize, 2019). Fig. 2 indicates that an additional $100 in payouts is associated with an increase the probability of ever breastfeeding of about 0.055 ([95% CI: 0.01, 0.1]) percentage points (pp) for mothers whose children are born in the month of payout (t = 0; 1st panel). An additional $100 is associated with increases the probability of breastfeeding at four weeks of about 0.09 pp ([95% CI: 0.01, 0.17]) for mothers whose children are born the month prior to the payouts (t = −1; 2nd panel). An additional $100 is also associated with significant increases the probability of breastfeeding at three months of about 0.09 pp ([95% CI: 0.005,0.17]) for mothers whose children are born two months before the payouts (t = −2; 3rd panel).

Table 2 shows that breastfeeding initiation and continuation vary by socioeconomic status and race. White mothers, mothers who are college educated, and mothers who did not receive Medicaid during pregnancy are more likely to start and continue to breastfeed than their non-White, less educated, and Medicaid recipient counterparts. Next, we investigate racial and socioeconomic variation in the associations between the Alaska Dividend and breastfeeding behaviors of Alaskans in urban areas. For ease of interpretation, we condense the months between November of t and July of t+1 into a single indicator (named “Other”). This allows us to focus on the months when we identified a significant pattern in the main models (i.e., the month of disbursement and the two months before the disbursement). Conclusions remain unchanged if we disaggregate these months (results available upon request).

Fig. 3 indicates that an additional $100 in payouts is associated with increases in the probability of breastfeeding initiation among mothers with no college education whose children were born in the month of disbursement (t = 0) of 0.11 pp ([95% CI: 0.03, 0.20]; 1st panel). The second panel reports on a 0.16 pp ([95% CI: 0.002, 0.32]) increase in the probability of breastfeeding at four weeks associated with $100 increases in payouts among mothers with some college education whose children were born one month before payouts (t = −1).

Fig. 4 shows that additional $100 in payouts is associated with a 0.10 pp ([95% CI: 0.01, 0.19]) significant increase in the probability of breastfeeding continuation at four weeks among non-Medicaid beneficiaries when children are born in the month of disbursement (t = 0; 2nd panel). Increases in payouts of $100 are also associated with significant increases in the probability of breastfeeding at three months among non-Medicaid beneficiaries whose children were born one or two months prior to disbursement (0.19 pp [95% CIt = -1: 0.06, 0.32; CIt = -2: 0.06, 0.32]); 3rd panel).

Fig. 5 reports on results by mothers’ race. Receiving an additional $100 is associated with significant increases in the probability of initiating breastfeeding among White mothers whose children were born in the month of disbursement (0.08 pp [95% CI: 0.006, 0.16], 1st panel). An additional $100 is also associated with significant increases in breastfeeding continuation at four weeks among mothers of “Other” race (0.23 pp [95% CI: 0.01, 0.44], 2nd panel). Finally, increases of $100 are associated with increases in breastfeeding continuation at three months among White mothers whose children were born two months before the payouts (0.16 pp [95% CI: 0.03, 0.29], 3rd panel) and mothers of “Other” race whose children were born one month before payouts (0.27 pp [95% CI: 0.002, 0.53], 3rd panel). We find no association between Dividend receipt and breastfeeding behaviors of AI/AN mothers.

The third panel of Fig. 6 suggests an increase in the probability of continuing to breastfeed at three months for married persons whose children were born one month (0.13 [95% CI: 0.01, 0.24]) or two months (0.14 [95% CI: 0.01, 0.27]) before disbursement. Mothers who are not married are significantly likely to increase breastfeeding continuation when their children are born in other months (Fig. 6, 1st panel). Additional analyses disaggregating months in the “Other” category (not shown) indicate that this increase is driven by significant changes in the probability of breastfeeding among non-married mothers whose children are born in April.

To understand the sensitivity of our results to the way we measured our key independent variable (size of the total Dividend payout received by a family), we conducted a series of robustness checks. First, we found that our proxy for family size (adding marital partner and number of previous births) yielded similar results to an alternative measure using the reported number of dependents on the prior years’ income (n = 14,987). Second, we find that using alternative monthly assignments of the Dividend values (to all months in a calendar year and to the 12 months following receipts instead of assigning it to the 6 months before and after October) corroborate main results. Finally, to ensure that our results are not being driven by fluctuations in household size, we conducted two tests: (1) We used a more conservative version of the model, controlling for both household-size fixed effects and year fixed effects, finding that results remain the same despite slightly larger standard errors; (2) We used a measure of individual rather than family payouts in our models, finding substantially smaller and statistically insignificant associations. Whereas the first test supports the use of our current measure, the second casts doubt on our findings. We conjecture, however, that discrepancies between these two sets of results may arise from much lower levels of variation in the key independent variable of interest when measured as individual payouts (i.e., eliminates all source of within-year variation). We opted for following previous literature (Amorim, 2022; Cowan & Douds, 2022; Hsieh, 2003; Kueng, 2018) and relying on the family rather than the individual Dividend in the main models.

We also tested the robustness of our results to the choice of controls and moderators included in our models. First, we used a restricted sample (n = 14,908) and an alternative measure of racial identities (that accounts for Hispanic origin) as controls in our models. These results corroborate our main analyses. Second, we used three alternative measures of economic standing as moderators in our models: (i) WIC receipt during pregnancy (full sample) (ii) public assistance (i.e., TANF, SNAP); receipt in the year prior to birth (collected in 1996–2008; n = 10,359); and (iii) economic insecurity (i.e., difficulty paying bills) in the 12 months prior to birth (full sample). Models using measures of public assistance receipt or economic insecurity in the year prior to birth corroborate main results, finding that cash transfers increase breastfeeding continuation only among the most economically advantaged mothers (who did not receive public aid or who did not have trouble paying bills before childbirth). Models using WIC receipt as a proxy for economic standing suggest that both mothers who did and did not receive WIC increase their likelihood of breastfeeding continuation as payouts increase. Notably, compared to other proxies for economic standing, WIC is received by a larger proportion of our sample (44%) and the program's income requirements are less stringent – i.e., WIC recipients are likely more economically advantaged than Medicaid recipients, public assistance beneficiaries, and mothers who experienced difficulties paying bills in the year before birth.

We conducted two supplemental analyses to test how restricting our sample to urban Alaskans influence our conclusions. First, we reproduced our main models on a sub-sample of rural Alaskans (n = 8037) finding insignificant results. We then reproduced the main analyses on a sample of all Alaskans (rural and urban), controlling for rural residence (N = 23,492). Results from these models were also largely insignificant. These second set of results are unsurprising given that rural Alaskans comprise a large proportion of the final sample (34.2%) and that the role of rural residence is expected to be interactive.

PRAMS data do not contain measures of mothers' work/leave status consistently from 1996 to 2016. Using a sample restricted to the years 2012–2015 (n = 2234), we created a categorical variable accounting for mothers' work/leave status (left workforce after birth; received paid leave after birth; used unpaid leave after birth; had no leave after birth; was not working while pregnant) to test the relevance of these potential confounders. Table 3 below first reproduces results from our main models with the restricted 2012–2015 sample. A comparison of AMEs presented in Fig. 2 and in Panel A of Table 3 indicates that this sample restriction changes the associations of interest, deeming them smaller, noisier, and largely insignificant. Keeping the 2012–2015 restricted sample, Panel B adjusts for mothers’ work/leave status. We find that controlling for work/leave status does not change the significance, direction, or magnitude of the associations between payout sizes and breastfeeding shown in Panel A. We find that the AMEs presented in Panels A and B (as well as underlying coefficients, not shown) are not significantly different than each other using the -khb- command in Stata (Karlson et al., 2012).

We find that universal payouts increase the probability of breastfeeding among Alaskan mothers in urban areas. Notably, supplemental analyses suggest that there are no significant associations between payouts and breastfeeding among mothers in rural areas – possibly due to the unique remoteness, practice of subsistence, and the prevalence of non-cash economies in rural Alaska. In urban areas, payouts increase the probability of initiating breastfeeding when they are received in the month of birth. They also promote breastfeeding continuation during the period in which they are received (e.g., continuation at 4 weeks for children born about one month before the transfer). Importantly, the impacts of payouts are substantially large: when receiving the average family payout ($5185), mothers who give birth in the month of disbursement increase their probability of ever breastfeeding by about 2.6 pp [0.05 × (5185/100)] and mothers who give birth one and two months before disbursement see an increase in the probability of breastfeeding at four weeks and three months, respectively, of 4.7 pp [0.09 × (5185/100)]. Notably, we found greater associations between cash influxes and breastfeeding continuation rather than initiation; This suggests that cash influxes may be linked to longer breastfeeding duration among mothers who already planned to breastfeed. The associations between universal transfers and breastfeeding vary along socioeconomic lines. First, we find that increases in payouts promote breastfeeding among mothers with less than a college degree and that increases in payouts support breastfeeding continuation among mothers who are relatively economically advantaged (who did not receive Medicaid during pregnancy, but also who did not receive public assistance and who did not have trouble paying bills in the year before birth). These results suggest that human and economic capital have different implications for breastfeeding. Whereas college-educated mothers may already plan to breastfeed regardless of payouts, mothers with less education (net of socioeconomic resources) may alter their plans for breastfeeding initiation because of payouts. On the other hand, net of educational background, mothers with more economic resources may be able to take better advantage of payouts (by increasing work leaves for example). This is particularly true if payouts are not enough to reduce experiences of economic hardship (and ensuing need for labor force participation) among economically challenged families. In tandem, married mothers, who arguably have more social resources than non-married mothers, are the ones most likely to increase breastfeeding continuation in response to increasing payouts (also see Bibler et al., 2019). Mothers who are not married, on the other hand, are significantly likely to increase breastfeeding continuation when their children are born in April. We hypothesize that this increase in breastfeeding during spring may be driven by tax credits/refunds among more disadvantaged single mothers (Hamad & Rehkopf, 2015). Finally, we investigate racial disparities in the associations between cash transfers and breastfeeding. Our results using race as a moderator should be interpreted as reflecting the consequences of structural racism on social determinants of health rather than resulting from biology or identity. Payouts increase breastfeeding among both White mothers and mothers of “Other” races, but not among AI/AN mothers. The associations between payouts on mothers of “Other” races and breastfeeding behaviors is restricted to continuation, suggesting that payouts may not alter previously established plans for not breastfeeding (Nommsen-Rivers et al., 2010), but still support longer breastfeeding periods among those who planned on breastfeeding. The lack of significant associations in the focal relationship among AI/AN mothers could be due to structural reasons, cultural reasons, or even health-related reasons shaping breastfeeding that deem payouts less relevant to decision-making (Louis-Jacques et al., 2017; Spieler, 2010). Notably, AI/AN mothers may receive other meaningful payouts in other months of the year through the Alaska Native Regional Corporations. Although the proportion of mothers receiving payouts, the size of payouts, and the timing of payouts are unknown, it is possible that they make the contrast between births occurring around the time of the Dividend disbursement and other months less salient. Our study finds that universal payouts are associated with increased in the likelihood of breastfeeding initiation and/or continuation among certain sub-groups (e.g., mothers who identify as White or “other race,” low educated mothers) but not others (AI/AN mothers, Medicaid recipients, rural residents). One potential explanation for these patterns could be differing work patters in these populations (if for example, Medicaid recipients, AI/AN mothers, rural, or non-m mothers are less likely to work full-time). Thus, some of our findings may be explained by important omitted confounders, namely, mothers' work status before pregnancy and/or leave duration after birth. In supplemental analyses with a restricted sample (described in section 4.3) we find suggestive evidence that the association between income support and breastfeeding is not explained away by mothers’ work/leave status. Although these results provide tentative support to the credibility of our main conclusions, they need to be interpreted with caution given that they rely on much smaller sample and lower levels of variability in the payout sizes. Future studies using better measures of labor supply, a longer time span, and appropriate time ordering are needed to better understand the potentially confounding and mediating relationships between work, leave, and income support. This paper has other important limitations. First, PRAMS data do not measure income consistently, and there is no measure of mothers' cohabitation status. This limitation led us to use coarse proxies for economic status and family size. Second, we impute the Dividend amount received by a family, without knowing if all families in our data qualified to receive a payout or received their payout in full (payouts may be garnished for different reasons, such as incarceration). This may have led to attenuation bias in our estimates. Third, our models capture how increases in benefit size shape breastfeeding, but they provide little insight into how creating new benefits may promote breastfeeding since we do not have data before the Dividend's implementation in 1982. Fourth, it is possible that the Dividend affects women's pregnancy plans, skewing births from mothers who plan to breastfeed to the last quarter of the year. Finally, this study was unable to test potential pathways through which payouts can shape breastfeeding such as reductions in stress, improvements in mental health, access to social support, and changes in labor supply. Future studies should further investigate these specific pathways and establish causal relationships. Despite these limitations, this study has important policy and theoretical implications for understanding the role of universal cash transfers in breastfeeding outcomes. Overall, our results corroborate previous studies of means-tested cash transfers (Hamad & Rehkopf, 2015; Sen et al., 2020) and provides evidence that universal cash transfers, another type of distal intervention, improve breastfeeding. This type of intervention has the potential to remove financial barriers to breastfeeding initiation and, in particular, continuation. The role of payouts in extending the length of breastfeeding duration suggests that income support may be particularly effective among women who would like to breastfeed but whose autonomy is being compromised by financial circumstances.

The authors declare no conflicts of interest. There are no financial interests or relationships with outside entities that could bias the design, conduct or reporting of this research study.

Mariana Amorim: Conceptualization, Methodology, Formal analysis, Writing (Original draft), Erica Hobby Formal analysis, Writing (Original draft), Anna Zamora-Kapoor Conceptualization, Writing (Review & Editing), Katherine A. Perham-Hester: Supervision, Writing (Review & Editing), Sarah K. Cowan Conceptualization, Methodology, Writing (Review & Editing)

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.