Designed for equity? Studies on parental leave and the mental health of parents

The transition to parenthood is regarded as an exciting time for prospective parents; however, it can also be a challenging period marked by uncertainty, stress, and anxiety. These challenges may arise from biological and hormonal changes, as well as a range of socio-emotional and psychosocial pressures, as well as financial pressures due to time off work and the prospect of reduced income, all of which can impact mental health. Mental disorders are common in the postpartum period, with postpartum depression affecting an estimated 17% of mothers and 9% of fathers globally. Generous parental leave may help alleviate mental health symptoms by reducing financial stress and providing job-protected time for parents to recover from childbirth and bond with their child. However, access to generous parental leave is generally linked to an individual's attachment to the labour market, meaning that those with weaker labour market ties are less likely to qualify for more generous benefits. As a result, the work requirement for eligibility for generous parental leave may contribute to widening health inequalities in society. Using the Social Determinants of Health framework, which recognises that health is shaped by the social, economic, and environment conditions in which people live, this thesis aims to deepen our understanding of the relationship between parental leave generosity and poor mental health of parents. The thesis draws data from a systematic review of peer-reviewed international literature as well as empirical studies using Swedish population registers.Study I systematically reviewed peer-reviewed international literature on the effects of different aspects of parental leave generosity, including remuneration and duration of leave, on both mothers' and fathers' mental health after childbirth. Overall, mothers generally experienced better mental health both in the postpartum period and in later life with more generous parental leave policies such as, paid leave and longer duration, compared to those with shorter or unpaid leave. Although findings for fathers were less conclusive due to fewer studies, available evidence suggests that fathers also benefit from policies that offer adequate wage replace or incentives, such as individual uptake quotas. The review identified several key knowledge gaps. First, no studies have explicitly considered the role of work requirements for eligibility for paid parental leave in relation to parental mental health. Second, many observational studies did not account for mental health conditions before parenthood, which limits the ability to distinguish whether postpartum symptoms reflect new onset of poor mental health or a continuation of pre-existing mental health conditions. Third, evaluations of paid parental leave often lack clear and consistent comparison groups. Lastly, there is limited research on fathers, which may contribute to the inconclusive findings regarding the effects of parental leave on fathers' mental health. These knowledge gaps have guided the subsequent empirical studies of the thesis.Study II examined whether first-time mothers with poor health before pregnancy were less likely to be eligible for more generous parental leave benefits in Sweden. The study found that mothers with preconception health conditions, particularly those with mental disorders or those with chronic health conditions (except musculoskeletal conditions), were less likely to qualify for more generous paid benefits. These findings suggest there is health selection into parental leave entitlements and that the strong work requirement for qualifying for generous parental leave may unintentionally reinforce socioeconomic inequalities between mothers with and without prior health conditions.Studies III and IV evaluated the association between levels of paid parental leave benefits and postpartum mental health (examined through differing levels of severity and healthcare utilisation) in first-time mothers (Study III) and fathers (Study IV) in Sweden. Overall, both mothers and fathers who received higher-level paid parental leave benefits generally experienced better postpartum mental health than those receiving basic paid benefits even after accounting for key variables that influence eligibility for higher-level paid benefits: mental health conditions before parenthood, income and employment status. Specifically, mothers receiving higher-level benefits were less likely to receive care for moderate-to-severe mental disorders, while fathers were less likely to receive any mental healthcare across all levels of severity, compared to those receiving only basic benefits. These findings suggest that more generous parental leave benefits could promote postpartum mental health for mothers and fathers.This thesis demonstrates that generous parental leave can positively support postpartum mental health for both mothers and fathers. However, it also highlights how strict work requirements to qualify for better paid benefits reinforces structural inequalities. The parental leave scheme may unintentionally exclude those most in need of support during the transition to parenthood since eligibility for more generous benefits are tied to labour market attachment. Policies that promote stable employment prior to childbirth and relax strict work requirements could help support postpartum mental health. These findings should be carefully considered by policymakers when designing or reforming parental leave schemes. Overall, this thesis underscores the importance of applying a Health in All Policies approach, which considers the health implications across all public policies, to address postpartum mental health.List of scientific papersI. Heshmati A, Honkaniemi H, Juárez SP. The effect of parental leave on parents' mental health: a systematic review. The Lancet Public Health. 2023; 8(1): e57-e75. https://doi.org/10.1016/s2468-2667(22)00311-5II. Heshmati A, Dunlavy A, Mussino E, Fritzell S, Juárez SP. Health before pregnancy and eligibility for parental leave benefits: a Swedish total population cohort study. BMC Public Health. 2025; 25: 1045. https://doi.org/10.1186/s12889-025-22248-8III. Heshmati A, Honkaniemi H, Fritzell S, Juárez SP. Parental leave benefits and maternal postpartum mental health in Sweden. JAMA Network Open. 2025; 8(4):e258062. https://doi.org/10.1001/jamanetworkopen.2025.8062IV. Heshmati A, Juárez SP. Parental leave benefits and paternal mental health: a Swedish register-based cohort study. Manuscript