The research, published in the journal Genus by sociologist Sarah Schmauk of the Hertie School in Berlin and Anna-Karin Nylin of Stockholm University’s Demography Unit, is one of the first to track the long-term individual labour earnings of separated and partnered first-time mothers across two contrasting welfare states. Drawing on population-wide Swedish register data and a large sample from the German public pension insurance system, the authors followed women who gave birth to their first child between 1992 and 2014, from one year before the birth until ten years after it. The Swedish sample comprised 688,713 women and more than seven million person-years of observation; the West German sample included 25,548 women followed over 246,585 person-years.

The methodological design is deliberately comparative. Sweden and West Germany represent two distinct social policy archetypes. Sweden built its “dual-earner dual-carer” model from the 1970s onward, combining individualised taxation, income-related parental leave, subsidised public childcare used by nearly all children by age two, and legal rights to reduce working hours for parents of young children. West Germany, by contrast, long supported a male breadwinner arrangement: married women were covered by their spouse’s health insurance, joint taxation created strong disincentives for second earners, and access to public childcare remained limited well into the 2000s. Although Germany reformed its policies after 2000—introducing earnings-related parental leave benefits in 2007, father leave incentives, and a legal right to a childcare slot from age one in 2013—the study period still captures a system in which maternal full-time employment remained unusual.

The analytical strategy relies on fixed-effects regression models, a technique that uses each woman as her own control. Because the data contain repeated annual measures of earnings for every individual, the models can estimate how separation changes a mother’s earnings net of stable unobserved characteristics, such as personality or family background, while also controlling for the number of children, maternal age, annual female unemployment rates, and historical period. The dependent variable is annual gross labour earnings in euros, converted to 2014 values, and kept in absolute amounts rather than log-transformed so that women with zero earnings in a given year remain in the analysis. To probe socioeconomic differences, the researchers classified mothers into quartiles based on their earnings two years before the first birth—a point chosen because it precedes both the anticipation of parenthood and any selection effects tied to separation.

The headline results are strikingly country-specific. In Sweden, separation is negatively linked to earnings: separated mothers earn on average 1,052 euros less per year than partnered mothers. In West Germany, separation is positively linked to earnings: separated mothers out-earn partnered mothers by 1,886 euros per year on average. These figures confirm the study’s hypotheses, which were derived from the interplay of “push” and “constraining” factors in each policy context.

Push factors are pressures that drive mothers to work more after separation: the loss of economies of scale, the splitting of pooled household income, the end of “marriage benefits” such as spousal health insurance coverage, and unreliable child maintenance payments. West German mothers, the authors argue, face these pressures most acutely because fewer of them were fully integrated into the labour market after childbirth. Separation therefore functions as an economic shock that forces many to seek regular employment or extend their hours. In Sweden, where most mothers already work close to full-time after childbirth, the push to increase earnings is weaker. Instead, separated Swedish mothers confront constraining factors—chiefly the time-allocation conflicts of raising children alone while holding a job in a system where full-time work is the norm. These constraints can lead them to reduce hours, forgo career advancement, or accumulate human capital depreciation over time.

The long-term trajectories add an important nuance. In Sweden, both partnered and separated mothers eventually surpass their pre-birth earnings levels, but the trajectories of separated mothers cross over and begin to lag behind those of partnered mothers from around four to five years after childbirth. This lag holds across all earnings quartiles but is most severe for mothers in the lowest quartile, whose shortfall hovers around 10 percent, compared with roughly 5 percent for the rest. In West Germany, the earnings advantage of separated mothers emerges only among those in the upper two pre-birth earnings quartiles, becoming statistically significant from four years after the birth onward. Mothers in the lowest quartile show flat trajectories whether partnered or separated, suggesting they lack the resources—human capital, work experience, and occupational networks—to translate economic need into higher earnings. West German mothers thus split into two groups: those who can respond to separation with higher earnings and those who cannot.

Even the “winners” in the German case fall short of genuine economic autonomy. Ten years after childbirth, West German mothers on average earn 8,570 euros less annually than before the birth, while Swedish mothers earn 15,650 euros more. In other words, although separation pushes some West German mothers upward relative to their partnered peers, virtually all remain far below their pre-birth earnings. The gendered division of labour after childbirth, longer employment interruptions, part-time work—39 percent of German mothers work fewer than 30 hours per week, versus 9 percent in Sweden—and a larger gender wage gap all contribute to this persistent shortfall.

The study’s subgroup analysis speaks to the theory of cumulative disadvantage. Mothers with lower education and weaker labour market attachment accumulate less human capital and are less competitive when trying to re-enter work or switch to better-paying jobs, even though their economic need after separation is greatest. Selection compounds the problem: separation is more common in the lower earnings quartiles in both countries, and single parenthood carries a strong negative educational gradient. The researchers also note that previous findings questioning whether “family-friendly” policies truly reduce gender inequality—such as Finnish evidence that single mothers have substantially lower mid-life earnings than married mothers—resonate with their Swedish results. Policies that support mothers who follow a normative life course of stable partnership may leave single mothers exposed, even in the Nordic model.

The authors are careful about limitations. German data allowed them to identify only marital separations, not dissolutions of cohabiting unions, which remain a small but growing fraction in West Germany. East Germany had to be excluded because its family patterns differ substantially. Civil servants are absent from the pension data, and the number of separated mothers was too small to model the timing of separation—whether it occurred when the child was very young or later—separately. Selection into separation cannot be fully ruled out despite the fixed-effects design and the use of pre-birth earnings quartiles.

The policy implications are pointed. The authors warn that the “Scandinavization” of European social policy often brings welfare cuts justified by the assumption that women can now support themselves—Germany’s 2008 alimony reform, which presumed mothers become “self-reliant” once the youngest child turns three, is a case in point. Such cuts risk dismantling a financial safety net that single mothers urgently need, including those who worked full-time before separation. At the same time, the Swedish findings show that even the most generous family-friendly policies do not fully protect separated mothers, who earn less than partnered mothers while lacking a second income. The authors call for broad bundles of measures: regulated child maintenance, social benefits, work arrangements, and childcare systems that ease time conflicts for lone parents. Their closing observation is blunt: being a single “earner-carer” in a “dual-earner” context appears to lead, almost inevitably, to poorer economic outcomes for women.