Historically, reforms that have increased the duration of job‐protected paid parental leave have improved women's economic outcomes. By targeting the period around childbirth, access to paid parental leave also appears to reduce rates of infant mortality, with breastfeeding representing one potential mechanism. The provision of more generous paid leave entitlements in countries that offer unpaid or short durations of paid leave could help families strike a balance between the competing demands of earning income and attending to personal and family well‐being. Context Policies legislating paid leave from work for new parents, and to attend to individual and family illness, are common across Organisation for Economic Co‐operation and Development (OECD) countries. However, there exists no comprehensive review of their potential impacts on economic, social, and health outcomes. Methods We conducted a systematic review of the peer‐reviewed literature on paid leave and socioeconomic and health outcomes. We reviewed 5,538 abstracts and selected 85 published papers on the impact of parental leave policies, 22 papers on the impact of medical leave policies, and 2 papers that evaluated both types of policies. We synthesized the main findings through a narrative description; a meta‐analysis was precluded by heterogeneity in policy attributes, policy changes, outcomes, and study designs. Findings We were able to draw several conclusions about the impact of parental leave policies. First, extensions in the duration of paid parental leave to between 6 and 12 months were accompanied by attendant increases in leave‐taking and longer durations of leave. Second, there was little evidence that extending the duration of paid leave had negative employment or economic consequences. Third, unpaid leave does not appear to confer the same benefits as paid leave. Fourth, from a population health perspective, increases in paid parental leave were consistently associated with better infant and child health, particularly in terms of lower mortality rates. Fifth, paid paternal leave policies of adequate length and generosity have induced fathers to take additional time off from work following the birth of a child. How medical leave policies for personal or family illness influence health has not been widely studied. Conclusions There is substantial quasi‐experimental evidence to support expansions in the duration of job‐protected paid parental leave as an instrument for supporting women's labor force participation, safeguarding women's incomes and earnings, and improving child survival. This has implications, in particular, for countries that offer shorter durations of job‐protected paid leave or lack a national paid leave entitlement altogether.

BackgroundVitamin D regulates bone mineral metabolism and skeletal development. Some observational studies have suggested that prenatal vitamin D deficiency increases the risk of adverse pregnancy and/or birth outcomes; however, there is scant evidence from controlled trials, leading the World Health Organization to advise against routine vitamin D supplementation in pregnancy. Importantly, little is known about the effect of maternal vitamin D status on infant linear growth in communities in South Asia where stunting is highly prevalent and maternal-infant vitamin D status is commonly suboptimal.Methods/DesignThe Maternal Vitamin D for Infant Growth study is a randomized, placebo-controlled, dose-ranging trial of maternal vitamin D supplementation during pregnancy and lactation in Dhaka, Bangladesh. The primary aims are to estimate (1) the effect of maternal prenatal oral vitamin D3 supplementation (4200 IU/wk, 16,800 IU/wk, or 28,000 IU/wk, administered as weekly doses) versus placebo on infant length at 1 year of age and (2) the effect of maternal postpartum oral vitamin D3 supplementation (28,000 IU/wk) versus placebo on length at 1 year of age among infants born to women who received vitamin D 28,000 IU/wk during pregnancy. Generally healthy pregnant women (n = 1300) in the second trimester (17–24 weeks of gestation) are randomized to one of five parallel arms: placebo 4200 IU/wk, 16,800 IU/wk, or 28,000 IU/wk in the prenatal period and placebo in the postpartum period or 28,000 IU/wk in the prenatal period and 28,000 IU/wk in the postpartum period. Household- and clinic-based follow-up of mother-infant pairs is conducted weekly by trained personnel until 26 weeks postpartum and every 3 months thereafter. The primary trial outcome measure is length for age z-score at 1 year of age. Anthropometric measurements, clinical information, and biological specimens collected at scheduled intervals will enable the assessment of a range of maternal, perinatal, and infant outcomes.DiscussionThe role of vitamin D in maternal and infant health remains unresolved. This trial is expected to contribute unique insights into the effects of improving maternal-infant vitamin D status in a low-income setting where stunting and adverse perinatal outcomes represent significant public health burdens.Trial registrationClinicalTrials.gov identifier: NCT01924013. Registered on 13 August 2013Electronic supplementary materialThe online version of this article (doi:10.1186/s13063-015-0825-8) contains supplementary material, which is available to authorized users.

Many have called for greater inclusion of researchers from low- and middle-income countries (LMICs) in the conduct of global health research, yet the extent to which this occurs is unclear. Prior studies are journal-, subject-, or region-specific, largely rely on manual review, and yield varying estimates not amenable to broad evaluation of the literature. We conducted a large-scale investigation of the contribution of LMIC-affiliated researchers to published global health research and examined whether this contribution differed over time. We searched titles, abstracts, and keywords for the names of countries ever classified as low-, lower middle-, or upper middle-income by the World Bank, and limited our search to items published from 2000 to 2017 in health science-related journals. Publication metadata were obtained from Elsevier/Scopus and analysed in statistical software. We calculated proportions of publications with any, first, and last authors affiliated with any LMIC as well as the same LMIC(s) identified in the title/abstract/keywords, and stratified analyses by year, country, and countries’ most common income status. We analysed 786 779 publications and found that 86.0% included at least one LMIC-affiliated author, while 77.2% and 71.2% had an LMIC-affiliated first or last author, respectively; however, analagous proportions were only 58.7%, 36.8%, and 29.1% among 100 687 publications about low-income countries. Proportions of publications with LMIC-affiliated authors increased over time, yet this observation was driven by high research activity and representation among upper middle-income countries. Between-country variation in representation was observed, even within income status categories. We invite comment regarding these findings, particularly from voices underrepresented in this field.