This year's Mother's Day may not have been the happiest for working moms. As families still shelter in their homes to protect themselves from COVID-19, a lot of moms are, as usual, doing more than their fair share of child care while (impossibly) trying to teach out-of-school kids and work remotely. And moms like me who are doing this are, of course, among the lucky ones — we haven’t lost our incomes. But there’s something fairly easy and cost-free that employers can do to attract, support and retain working mothers, during and after this pandemic: Offer us predictable hours and work commitments.

Unpredictability is one of the biggest challenges working moms face — in all kinds of professions. It helps explain why highly educated mothers on the whole don’t earn more and go further in their careers. Between 1984 and 2014, the hourly pay of people who work long hours increased dramatically, according to research by the Russell Sage Foundation. Top-paying jobs in fields like finance, consulting and law often require long and unpredictable hours, so it’s hard for two people in the same family to hold such positions. If both parents have to jump on last-minute flights, who will be home for the kids? That sort of responsibility still mostly falls to mothers, which helps explain why many highly educated moms don’t hold top positions.

The Russell Sage study also found that the long hours that now come with top-paying jobs helps explain the so-called motherhood wage penalty and fatherhood wage premium — the reason moms make less money than childless women and dads make more money than childless men. According to a 2018 study of Census data by the National Women’s Law Center, the motherhood penalty costs the average mom $16,000 a year in lost wages.