How Infant Health Shapes Maternal Earnings

Parenthood remains a major driver of economic inequality between men and women, yet little is known about how differences in infant health at birth shape this gap. This paper examines whether early-life health endowments — specifically low birth weight and preterm birth — affect mothers’ long-term earnings trajectories and intra-household income composition. Using linked Canadian administrative data covering all births from 2006 to 2015 and annual family tax files, I estimate the causal impact of poor infant health with a matched event study design. The results show that mothers of infants in poor health earn about 1.6% less one year after birth, rising to over 3.5% by year seven, mainly due to increased labor force exit. Affected mothers are 3.4% less likely to contribute at least 40% of household income six years after birth, widening intra-household inequality. While partners experience similar short-term earnings effects, these fade in the longer term, highlighting how the burden of poor infant health increasingly falls on mothers. Importantly, this asymmetry is not explained by differences in couple dissolution patterns. Mediation analysis suggests that caregiving demands linked to childhood health vulnerabilities — rather than declines in mothers’ own health — are the dominant channel. Variation across provinces further suggests that generous family policies, such as Quebec’s parental leave program, mitigate the penalty only in the short term. These findings highlight how improving infant health at birth can complement family policies aimed at closing the gender earnings gap. JEL Classification: J13, J22, I14