Association between maternal employment status and presence of children with major congenital anomalies in Denmark
Authors: Kim Kyung Mi , Farkas Dóra Körmendiné , Wong Venus , Hjorth Cathrine Fonnesbech , Horváth-Puhó Erzsébet , Cahan Eli , Cohen Eyal , Shah Nirav R. , Sørensen Henrik Toft , Milstein Arnold 
Published: March 2024

Abstract
Importance
The burden of caring for children with complex medical problems such as major congenital anomalies falls principally on mothers, who in turn suffer a variety of potentially severe economic consequences. As well, health consequences of caregiving often further impact the social and economic prospects of mothers of children with major congenital anomalies (MCMCAs). Evaluating the long-term economic consequences of extensive in-home caregiving among MCMCAs can inform strategies to mitigate these effects.

Objective
To assess whether MCMCAs face reduced employment and increased need for disability benefits over a 20-year period.

Design
A population-based matched cohort study.

Setting
Denmark.

Participants
All women who gave birth to a singleton child with a major congenital anomaly in Denmark between January 1, 1997 and December 31, 2017 (n = 23,637) and a comparison cohort of mothers matched by maternal age, parity, and infant’s year of birth (n = 234,586).

Exposures
Liveborn infant with a major congenital anomaly.

Main outcomes and measures
The primary outcome was mothers’ employment status, stratified by their child’s age. Employment status was categorized as employed, outside the workforce (on temporary leave, holding a flexible job, or pursuing education), or unemployed; the number of weeks in each category was measured over time. The secondary outcome was time to receipt of a disability pension, which in Denmark implies permanent exit from the labor market. We used a negative binomial regression model to estimate the number of weeks in each employment category, stratified by the child’s age (i.e., 0–1 year, > 1–6 years, 7–13 years, 14–18 years). A Cox proportional hazards regression model was used to compute hazard ratios as a measure of the relative risk of receiving a disability pension. Rate ratios and hazard ratios were adjusted for maternal demographics, pregnancy history, health, and infant’s year of birth.

Results
During 1–6 years after delivery, MCMCAs were outside the workforce for a median of 50 weeks (IQR, 6–107 weeks), while members of the comparison cohort were outside the workforce for a median of 48 weeks (IQR, 4–98 weeks), corresponding to an adjusted rate ratio [ARR] of 1.05 (95% confidence interval [CI], 1.04–1.07). During the first year after delivery, MCMCAs were more likely to be employed than mothers in the comparison cohort (ARR, 1.08; 95% CI, 1.06–1.10). At all timepoints thereafter, MCMCAs had a lower rate of workforce participation. The rate of being outside the workforce was 5% higher than mothers in the comparison cohort during 1–6 years after delivery (ARR, 1.05; 95% CI, 1.04–1.07), 9% higher during 7–13 years after delivery (ARR, 1.09; 95% CI, 1.06–1.12), and 12% higher during 14–18 years after delivery (ARR, 1.12; 95% CI, 1.07–1.18). Overall, MCMCAs had a 20% increased risk of receiving a disability pension during follow-up than mothers in the matched comparison cohort [incidence rates 3.10 per 1000 person-years (95% CI, 2.89–3.32) vs. 2.34 per 1000 person-years (95% CI, 2.29–2.40), adjusted hazard ratio, 1.20; 95% CI, 1.11–1.29].

Conclusion and relevance
MCMCAs were less likely to participate in the Danish workforce, less likely to be employed, and more likely to receive disability pensions than mothers of unaffected children. The rate of leaving the workforce intensified as their affected children grew older. The high demands of caregiving among MCMCAs may have long-term employment consequences even in nations with comprehensive and heavily tax-supported childcare systems, such as Denmark.