Maternity Leave and Its Impact on Breastfeeding: A Review of the Literature

Abstract

Background:

Breastfeeding is known to be the best source of nutrition for infants. The World Health Organization recommends to exclusively breastfeed up to the sixth month of life and to breastfeed with complementary foods until the age of 2. It is reported that maternity leave (ML) is one of the most important interventions for an extended breastfeeding duration. The aim of this review is to synthesize the available data worldwide on the association of ML and breastfeeding duration. We also intend to provide an overview of whether this association is differential by socioeconomic status.

Materials and Methods:

Relevant primary studies relating ML and breastfeeding were included by searching several databases, including PubMed, SCielo, Health Systems Evidence, Health Evidence, Cochrane Reviews, and Epistemonikos. Articles were included up to May 2018.

Results:

A total of 239 relevant articles were identified, of them 21 were included in the review based on exposure, outcome, and study design. These studies reported that an extended ML might be related to breastfeeding duration. In addition, studies reporting data on work type, race, and education showed that black women, women in less privileged position, and women with less education have less breastfeeding duration.

Conclusions:

This review showed a positive relationship between ML length and breastfeeding duration. These results have a homogeneous trend; however, this was different when studies reported results on ML and breastfeeding stratified by socioeconomic status. Public health policies should ensure that all women, especially the most vulnerable, have equal access to the benefits that ML provides.

Introduction

Breastfeeding has innumerable benefits for both the mother and the child. Vast literature has shown that breast milk is the best source of nutrition for the infant. Human milk also provides bioactive compounds that can modify the function of the digestive and immune system of the child, as well as brain development. These elements include digestive enzymes, immunoglobulins, growth factors, microbiota, among others.^1–7 Other benefits for the infant comprise possible diabetes and obesity prevention in adulthood.^1,2 In addition, increasing evidence shows the positive effects of breastfeeding for the mother, reducing breast and probably ovarian cancer, diabetes, and obesity risk, and a faster weight recovery after birth.² Breastfeeding also provides benefits to the family, country economy, and development, together with a reduction in infant mortality and morbidity.^2,8,9 For these reasons, the World Health Organization recommends that babies be exclusively breastfed (EBF) for at least 6 months, and continuing breastfeeding with complementary foods until at least the age of 2 years.³

To accomplish a successful breastfeeding, governments should promote policies that ensure that all mothers are empowered and supported to follow optimal infant breastfeeding practices. Successful and comprehensive breastfeeding strategies should include high-quality programs that encourage all women who want and can breastfeed, understanding that breastfeeding is always an investment for society and a key part in many of the United Nations' Sustainable Development Goals 2030.^8,10,11

According to 2016's Lancet series on breastfeeding,^2,8,12 until now, there is no country that has fully implemented these measures in breastfeeding strategies. These recommendations are based on comprehensive strategies at the government, community, and individual levels, targeting pregnant women and new mothers. Examples of these kinds of strategies and interventions are counseling and education, Baby-Friendly Hospital Initiative, cash transfers, maternity leave (ML), national-level pro-breastfeeding campaigns, among others.^8,10

ML and maternity protection strategies are among the interventions described as successful in breastfeeding promotion.^8,10,13 According to the International Labor Organization (ILO), ML is defined as one part of what is recognized as the legislative provisions of maternity protection, which includes ML, benefits, employment protection, health protection, breastfeeding arrangements at work, and childcare.¹⁴ Nonetheless, only recently the ILO advocated for maternity benefits to be delivered as part of the minimum basic social security guarantees for working women who want to breastfeed their children.

There is inconsistent and scarce information from previous studies regarding the relationship between ML and breastfeeding duration, especially among different socioeconomic levels and developing countries. Some studies are consistent in reporting the association between ML and breastfeeding. For example, Hawkins et al.¹⁵ found that women who had not returned to work by 6 months after birth had a higher prevalence of exclusive breastfeeding, but other studies showed mixed results.¹⁶ In this review of peer-reviewed studies, we aim to summarize and accumulate more evidence relating ML and breastfeeding duration. We intend to provide a narrative overview of the available evidence by clarifying whether there is an association between ML length and breastfeeding duration and whether this association is the same across all socioeconomic strata.

Materials and Methods

Search strategy

Initially, relevant articles relating ML and breastfeeding were identified by searching several databases, including PubMed, SCielo, Health Systems Evidence, Health Evidence, Cochrane Reviews,¹⁷ and the newly created Epistemonikos.¹⁸ Articles were searched up to May 2018. We had no year limit for this review.

Research question

The search looked for already published peer-reviewed articles that answered the research question and included data on exposure and outcome.

We followed the PICO (population, intervention, comparison, outcome) approach to orientate our research question, where: 1.

Population: working women

Intervention: ML duration

Comparison: no ML

Outcome: any breastfeeding duration

And the research question was: Is ML effective in promoting breastfeeding in working women equally according to socioeconomic status?

To address this question, the search strategy included articles with the keywords included in Table 1.

Table 1.

Keywords Included in the Search Strategy

Maternity leave (or)	AND	Breastfeeding (or)
Family leave		Breast milk
Parental leave		Breast feeding
Family and Medical Leave Act		Exclusive breastfeeding
Leave among parents
Medical leave
Work leave

Study selection

This review includes peer-reviewed articles with any of the following study designs: randomized trial, cohort, case–control, cross-sectional studies. Only studies that analyzed individual-level data were included. Articles assessing any type of modeling analysis or ecological study design were excluded.

Articles were included if the outcome was: exclusive breastfeeding duration/exclusive breastfeeding/exclusive “yes or no”, and the exposure was ML (paid and unpaid). We included studies written in English, Portuguese, and Spanish. Articles were also included if the methods section defined clear selection criteria, assessed the effects of ML on breastfeeding duration, and reported exclusive or any breastfeeding duration as the outcome. Studies that reported formula use as an outcome were also excluded.

Articles were first screened for title and abstract. Full text was screened if an article seemed relevant for inclusion.

Data extraction

The extraction of relevant data was performed by the author D.N.R. A summary table was prepared with the following data: first author's last name, year of publication, country where the study was conducted, sample size, sample description, study design, exposure description, outcome description, summary of results, and if the study included information stratified by socioeconomic status. Information on ML length and breastfeeding duration was included for many relevant subgroups. All data on breastfeeding and ML related to socioeconomic status or wealth were extracted, regardless of the type of analysis used.

Results

The search for this study yielded 239 articles, of which 216 were excluded based on title and abstract appraisal because they were written in a language other than English, Spanish, or Portuguese, or because they did not address the research question (Fig. 1). A total of 56 articles were screened for full-text review. Of these, access to full text was unavailable for 7 articles. Twenty-eight articles were excluded because the exposure or outcome was not relevant to the research question. Twenty-one articles were retained in the final review. Twelve of the included studies were located in the United States, Australia, or Europe (United Kingdom, Ireland, Spain), three in Asia (Israel, Jordan, and Turkey), three in South America (Brazil), two in South East Asia (Thailand and Myanmar), and one in Africa (Ghana). Eleven of the included studies had a cohort study design. All studies together counted for a total of 57,804 women.

FIG. 1.

Flowchart of study search and selection.

The 21 studies included in this review referred to ML and breastfeeding duration (Table 2). Camurdan et al.¹⁹ and Khasawneh and Khasawneh²⁰ describe ML time using days, Hmone et al.²¹ and Monteiro et al.²² provide a description of ML as working women versus not working women, while the rest of the studies that were included reported ML in weeks or months. The majority of studies included in this review outlined a ML of 12 weeks (3 months) or more. Breastfeeding was defined as exclusive in 5 studies, any breastfeeding (5 studies), predominant breastfeeding (2 studies), or total breastfeeding (exclusive) and any breastfeeding (16 studies). All the studies in this review defined the outcome as at least 3 months of breastfeeding.

Table 2.

Relationship Between Maternity Leave and Breastfeeding

Author, year	Country	Sample description	No. of participants	Study design	ML description		Outcome specification	Results (when shown 95% CI)	Stratification by socioeconomic status
Aikawa,²⁴ 2015	Thailand	Working mothers	84	Cross-sectional	≥3 vs. ≤3 months		BF duration at 3 months	AOR, 4.15 (1.15–14.94)	Not reported
Berger-Achituv,²³ 2005	Israel		1,665	Cross-sectional	≥2 weeks vs. no ML		Any BF duration at 2 weeks	OR, 1.6 (1.2–2.3); p = 0.003	Not reported
Berger-Achituv,²³ 2005	Israel		1,665	Cross-sectional	≥6 months vs. no ML		Any BF duration at 6 months	OR, 2.1 (1.1–4.0); p = 0.027	Not reported
Camurdan,¹⁹ 2008	Turkey	Mothers of medium–high socioeconomic status	1,230	Cross-sectional	>91 vs. ≤91 days ML		EBF at 3 months	RR, 2.19 (1.11–4.30)	Not reported
					>91 vs. ≤91 days ML		EBF at 6 moths	RR, 1.78 (1.15–3.41)	Not reported
					>181 vs. ≤91 days		BF	12.4 vs. 9.03 months; p = 0.001	Not reported
Dagher,²⁵ 2016	United States	Women participating in the Maternal Postpartum Health Study; employed while hospitalized for childbirth	817	Cohort	≤6 months vs. not returning to work		BF cessation during the first 6 months	Adjusted HR, 1.46 (1.14–1.87)	Adjusted HR for BF cessation during the first 6 months was lower for professional vs. clerical workers (0.71; 0.56–0.89)
Dun-Dery,²⁶ 2016	Ghana	Professional working mothers, defined as professional working mothers	369	Cross-sectional	≥3 vs. ≤3 months		EBF	AOR, 0.09 (0.02–0.45)	Not reported
Escribà Agüir,²⁷ 1996	Spain	Professional working women	545	Cohort	Back to work 5 months vs. 1 year ML		Months of BF	3.1 months vs. 3.5 months of BF (p = 0.005)	Not reported
					≤12 weeks vs. 1 year ML		BF	2.8 vs. 3.5 months; p = 0.005	Not reported
Guendelman,²⁸ 2009	United States, California		770	Cohort selected from a previous case–control study	6 months		BF cessation	AOR adjusted for education and income, 2.65 (1.51–4.66)	Women working in managerial roles were less likely to cease BF than those in lower-level positions (AOR: 0.63; [0.41–0.96])
					6–12 weeks			2.11 (1.20–3.73)
					<6 weeks			3.47 (1.63–7.38)
					No return no work (reference)			1
Hawkins,¹⁵ 2007	United Kingdom	British/Irish white employed mothers with singleton babies	6,917	Cohort	<3 months		BF for at least 4 months	RR, 0.81 (0.68–0.96)	Mothers who were not prompted by financial need to return to work early had a higher chance of BF for at least 4 months, compared to mothers who did return early because of economic circumstances (RR: 0.86; [0.80–0.93])
					4 months			RR, 0.74 (0.63–0.87)
					5 months			1.00
					6 months			RR, 1.25 (1.07–1.47)
					7 months			RR, 1.53 (1.34–1.74)
					8 months			RR, 1.54 (1.36–1.73)
Hmone,²¹ 2017	Myanmar		353 (24 for qualitative questionnaire)	Cross-sectional, selected from a randomized controlled trial, enrolled through the antenatal clinic, Central Women's Hospital	Working women vs. not working women		Intention EBF	AOR, 0.30 (0.17–0.53)	Qualitative results: Work was the main perceived barrier to practice EBF: “Work is the main barrier. I sell fried rice and could take time off only 4–6 weeks after delivery. How could I BF if there are a lot of customers.”“I work in a private company and get 2 months' maternity leave. It's impossible for me to give breast milk exclusively for 6 months.”All women perceived work was the main obstacle to EBF due to not enough maternity leave especially in private sector and the lack of BF-supporting environment.
Khasawneh,²⁰ 2017	Jordan	Middle-class women, with health insurance coverage	500	Cross-sectional	70–90 days		Full or partial cessation of BF at the end of ML	65%	Not reported
Mandal,²⁹ 2010	United States	Nationally representative	1,470	Cohort (The Infant Feeding Practices Study II)	≤12 weeks, <35 hours		BF duration in weeks	28.3 (p ≥ 0.05)	Not reported
					≤12 weeks, 20–34 hours			32.0 (p ≥ 0.05)
					≤12 weeks, 1–19 hours			40.0 (p ≥ 0.05)
					>12 weeks, 35 hours			32.7 (p ≥ 0.05)
					>12 weeks, 20–34 hours			40.9 (p ≥ 0.05)
					>12 weeks, 1–19 hours			NS
					Not working			1
Mirkovic,³⁰ 2016	United States	U.S. National Survey of Family Growth	2,635	Cohort	≥6 months no paid ML		BF	24.9% of women	Not reported
					≥12 weeks of paid leave		BF at sixth month	50.1% of women
					1–5 weeks paid ML vs. women with no paid ML			AOR, 1.23 (0.73–2.07)
					6–11 weeks paid ML vs. women with no paid ML			AOR, 1.12 (0.72–1.74)
					≥12 weeks paid ML vs. women with no paid ML.			AOR, 2.26 (1.20–4.26)
Monteiro,²² 2017	Brazil		10,995	Cross-sectional	Working women vs. women with no ML		EBF interruption	Adjusted PR, 1.23 (1.11–1.37)	Not reported
Ogbuanu,¹⁶ 2011	United States	Nationally representative data	6,150	Cohort	Total ML: 1–6 weeks7–12 weeks≥13 weeksDid not take ML		Any BF duration >6 months	RR,10.97 (0.76–1.19)1.05 (0.81–1.31)1.16 (0.91–1.44)	Not reported
					Paid ML:1–6 weeks7–12 weeks≥13 weeksDid not take ML			10.85 (0.67–1.06)0.78 (0.56–1.03)1.04 (0.79–1.32)
					Time to return to work:1–6 weeks7–12 weeks≥13 weeksDid not take ML			10.91 (0.68–1.17)1.19 (0.90–1.52)1.25 (0.91–1.61)
					Total ML1–6 weeks7–12 weeks≥13 weeksDid not take ML		Predominant BF >3 months	11.01 (0.72–1.37)1.27 (0.89–1.72)1.09 (0.77–1.47)
					Paid ML:1–6 weeks7–12 weeks≥13 weeksDid not take ML			11.00 (0.71–1.36)0.92 (0.67–1.24)1.01 (0.71–1.39)
					Time to return to work:1–6 weeks7–12 weeks≥13 weeksDid not take ML			11.31 (0.95–1.77)1.99 (1.38–2.69)1.70 (1.05–2.53)
Queluz,³² 2012	Brazil		275	Cross-sectional	Paid job with ML Paid job without MLNo paid job		EBF <6 months	1OR, 3.08 (1.14–8.32); p = 0.027OR, 2.26 (1.19–4.30); p = 0.012	Not reported
Sattari,³¹ 2013	United States	Physicians	130	Cross-sectional	Increase in BF duration for each week increase in total ML (paid and unpaid)		BF duration	AOR, 0.14 (0.04–0.23); p = 0.005	Not reported
Scott,³³ 2006	Australia		587	Cohort	Mothers who returned to work <6 months		Discontinuing BF at 6 months	HR, 1.42 (1.08–1.88)	Not reported
					Returning to work between 6 and 12 months			HR, 1.63 (1.18–2.25)
					Not working at 12 months			1
					Mothers who returned to work <6 months		Any BF at 6 months	HR, 1.69 (1.28–2.34)
					Mothers who returned to work <6 months			HR, 1.50 (1.07–2.09)
					Returning to work between 6 and 12 months			HR, 1.50 (1.07–2.09)
					Not working at 12 months			1
Skafida,³⁴ 2012	Scotland		2,079	Cohort	No ML to 1 month ML		BF at 10 months	HR, 1.41 (0.94–2.10)	Not reported
					1–2 months ML			HR, 1.63 (1.06–2.52)
					2–3 months ML			HR, 1.50 (1.05–2.15)
					3–4 months ML			HR, 1.68 (1.12–2.53)
					4–5 months ML			HR, 1.50 (1.14–1.96)
					5–6 months ML			HR, 1.30 (0.99–1.71)
					6–10 months ML			HR, 1.00 (0.75–1.32)
					6–10 months ML			HR, 1.00 (0.75–1.32)
Smith,³⁷ 2015	Ireland		1,094	Cohort	<6 months ML		Any BF at 6 months	1	Not reported
					6 months ML			AOR, 0.93 (0.44–1.97)
					7–12 months ML			AOR, 2.76 (1.51–5.05); p = 0.001
Vianna,³⁵ 2007	Brazil		9,458	Cross-sectional	ML vs. no ML		Prevalenceof EBF at 4 months	29.6% vs. 8.9%; p = 0.005	Not reported
Visness,³⁶ 1997	United States		9,087	Cross-sectional	Women from pacific and mountain states	≤6 months ML	BF	OR, 0.54 (0.28–1.07)	% of BF after returning to work	64%	White professionals
										47%	White technical/sales/administrative
										48%	White women working on services
					Women with college education			OR, 0.66 (0.47–0.93)		48%	White women working on services
					Women with college education			OR, 0.66 (0.47–0.93)		38%	White women working on manufacturing
					Women without college education			OR, 1.03 (0.75–1.41)		38%	White women working on manufacturing
										53%	All employed white women
										42%	Black professionals
										46%	Black technical/sales/administrative
										36%	Black women working on services
										46%	Black women working on manufacturing
										43%	All black employed women

AOR, adjusted odds ratio; BF, breastfeeding; CI, confidence interval; EBF, exclusively breastfed; HR, hazards ratio; ML, maternity leave; PR, prevalence ratio.

Most of the 21 studies (20 studies) showed that having a longer ML was a protective factor for breastfeeding duration.^{15,16,19–37} Studies that reported ML of more than 3 months had overall three times the likelihood of maintaining breastfeeding at 3 months after birth compared to returning to work within 3 months after birth. Women who had ML of 6 months were 50% more likely to maintain their breastfeeding until the sixth month after birth. In contrast, women who had to return to work before the third month after delivery showed, on average, between a 20% and 40% more likelihood of discontinuing breastfeeding; however, this did not seem to be significant in all studies.

Qualitative data described in one study carried out in Myanmar²¹ reported that work was the main barrier for breastfeeding duration in working women, especially in the private sector where women have a contract. A study from Jordan²⁰ reported that 65% of working women stopped breastfeeding upon returning to work.

The results in a cohort study of 2,079 women in Scotland found that a ML of 6–10 months did not yield a statistically significant result on breastfeeding duration (hazards ratio, 1.00 [95% confidence interval (CI), 0.75–1.32]).³⁴

This review found little evidence from studies presenting additional stratified analysis by socioeconomic status^{15,21,25,28,36} (Table 2). Most studies were stratified by work type, education, and race as socioeconomic status proxies. Only one of these studies was carried out in a developing country²¹; the rest were performed in the United States and the United Kingdom. These studies showed that, on average, women who had high-profile jobs showed a greater likelihood of maintaining their breastfeeding for more extended periods. In addition, women working in managerial positions, versus other types of jobs, were also more likely to continue their breastfeeding for a longer time, showing that managerial roles might be a protective factor for breastfeeding (odds ratio [OR], 0.63; 95% CI, 0.41–0.96).²⁸

Another example is the research performed by Visness and Kennedy,³⁶ which also observed that job status might influence breastfeeding duration. Professional white women had a higher percentage of breastfeeding after returning to work (64%) compared to white women working in technical, administrative, or sales jobs (47%), white women working in services (48%), and white women employed in manufacturing (38%).

Visness and Kennedy³⁶ also included data on Afro-American women. These results showed that race was also an important factor for early breastfeeding cessation after returning to work (white women 53% vs. Afro-American women 43%). Afro-American women did not show a gradient of association between work position and breastfeeding duration, compared to white women.

Data on education and breastfeeding showed that women with college studies, who returned to work before 6 months after delivery, were more likely to continue breastfeeding (OR, 0.66; 95% CI, 0.47–0.93), compared to women without college education.³⁶

Discussion

To our knowledge, this review is one of the few pieces of literature that includes data on the impact of ML and breastfeeding duration from six continents. In addition, we also reviewed whether the association differs by socioeconomic status.

Most of the studies selected in this review reported that there is a positive association between ML and breastfeeding duration. This review found that women with a ML of 3 months presented at least 50% more likelihood to extend breastfeeding duration as compared to women who returned to work before this time. Women who had 6 months or more of ML showed at least 30% likelihood of maintaining their breastfeeding for at least the first 6 months.

Other reviews that analyzed the association between ML and breastfeeding duration are consistent with the findings of this study.^13,38,39 Returning to work is described as the main reason for an early breastfeeding cessation.^25,40,41 Hence, the reasons for a positive link shown between an extended ML and breastfeeding could be related to ML providing more time for women to bond with their babies, and encouraging ad libitum breastfeeding.^40–42 Moreover, ML could be associated with having more time at home, away from work, recovering from the physical stress of childbirth, and focusing on the infant.

The few studies that reported data on ML and breastfeeding stratified by job position, education, and race as proxies of socioeconomic status showed that returning to work shortly after birth is related to an early breastfeeding cessation. In addition, in one study,³⁶ job status results revealed that women in more privileged working roles had higher rates of breastfeeding at 6 months after returning to work. The reasons for this relationship could be that women in low-profile jobs have less flexibility for breastfeeding, get less work support such as nursery and lactation rooms, need to work extra hours, receive less family support, together with having less knowledge of the importance of breastfeeding. These results might also be linked with having shorter commutes and less stress triggered by work.^43–45

Although this review includes a large number of cases, the comparability among studies is limited, due to the differences between sample characteristics, study design, analysis, and the metrics of exposure and outcome.

Several limitations of this study are worth considering. This review is limited by the available articles and the included ones, written in English, Spanish, and Portuguese. We found seven articles that were not available in the public domain, mainly data published before the 1990s. In addition, this review did not separate paid versus unpaid leave. These are significant limitations when considering the implications of paid ML, especially when bearing in mind the relationship with breastfeeding duration. As mentioned earlier, the lack of study design consistency limits the comparability among studies. Another limitation of the study design is the causation; as most studies have a cross-sectional design, it is tough to assign a direct relationship between ML and breastfeeding duration.

Despite the methodological limitations mentioned above, this study advances knowledge in many ways. First, it provides enough data to suggest that ML could support a longer breastfeeding duration, especially for women in more vulnerable jobs. Secondly, to our knowledge, this is the first review that includes articles representing the Americas, Asia, Africa, Europe, Oceania, and South East Asia. Additionally, the conceptual outline of this review offers a structure for understanding the situation of ML in more vulnerable women and the implications of this on breastfeeding. Finally, this review also provides relevant data for public health policies, showing that ML legislations do not always offer the same guarantee to all women.

Conclusion

Regardless of the WHO recommendations for EBF for at least 6 months after birth and complemented breastfeeding with other foods until the age of 2, paid ML is still not a compulsory policy worldwide. There is an urgent need to reinforce global policies on breastfeeding that will ensure EBF for at least 6 months, especially to more vulnerable groups and to women from all socioeconomic levels. Public health policies should warrant that ML benefit all working women equally.

Footnotes

Acknowledgments

The submitted work was financially supported by the Chilean National Fund for Scientific and Technological Development (FONDECYT), under the grants 1130277 and 1150878. Deborah Navarro-Rosenblatt holds a Chilean Commission of Science and Technology student fellowship to perform a PhD at the School of Public Health, University of Chile, under the grant 21151097.

Disclosure Statement

No competing financial interests exist.

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