Part-time employment can be a life-time setback for earnings

"Two particular features of the position of women in the British labour market are the extensive role of part-time work and the large part-time pay penalty. Part-time work features most prominently when women are in their 30s, the peak childcare years and, particularly for more educated women, a crucial period for career building. This makes it essential to understand its impact on women's subsequent earnings trajectories. We find that the wage return to part-time experience is low -- negligible in lower skill occupations. Even more important channels contributing to the pay disadvantage of women working part-time are job changing, particularly when this involves occupational downgrading. Downgrading can lead to a permanent pay disadvantage for women following a spell in part-time work"--Forschungsinstitut zur Zukunft der Arbeit web site.