Motherhood takes a big toll on women, and not just the nine-month period spent growing another human being inside their bodies. After birth, women spend more time parenting their children and take on more of the cognitive load of planning and care. Now a study recently published in the Journal of Family Studies finds their health, relative to their male partners, suffers accordingly.

To investigate how parenthood affects the health of men and women, sociologists from the University of the Basque Country turned to data from the European Health Survey in Spain, a periodic questionnaire that surveys the Spanish population about a variety of health indicators, both physical and psychological. They looked at how these measures—specifically psychological well-being, perception of health, exercise, and more—differed between mothers and fathers. They found a remarkable gender gap.

“It was observed that, in men, neither the fact of being a father, nor family characteristics, affected the health indicators,” study author Anna Barbuscia said in a statement. “All parameters remained practically the same.”

In other words, whether they had one child, several children, or no children, men’s physical and psychological health stayed the same.

Read more: “The Pressure Moms Feel to Solve the World’s Problems”

Women’s questionnaire responses told a completely different story. The researchers found that women’s health varied according to the number and ages of their children. Moms living with just one child and moms living with adolescents seemed to suffer the most, with the highest levels of depressive symptoms and the lowest levels of self-reported health. According to the team, moms with just one child reporting poorer mental and physical health could be because that child is their first, and the transition to motherhood hits particularly hard.

“Caring for younger children usually demands greater physical effort, which may result in increased tiredness and poorer quality sleep,” explained Barbuscia. “Adolescence, on the other hand, has traditionally been considered the most stressful phase for both mothers and fathers.”

The health habits of moms also suffered when they had kids. Only 16 percent of mothers with young kids exercised regularly, compared to 30 percent of childless women. Men’s exercise habits, on the other hand, were completely unaffected by fatherhood.

There was at least one bright(ish) spot for moms. Mothers of toddlers reported relatively favorable levels of health and mental well-being, which the researchers credited to the rewards of motherhood. “Although early childcare is physically demanding, it may also be accompanied by higher emotional rewards, potentially buffering its negative health effects,” they wrote. (Then again, mothers of toddlers might not like to learn they’re living through their healthiest time for some time.)

Per the team, these findings mean moms need a break to invest in their health, and policymakers should take that into account when designing family-friendly policies. Or as Barbuscia put it, “If we want to build healthy families and encourage people to have children, we need to start by ensuring that raising children doesn’t have such an unequal impact on men and women.”

Lead image: GarkushaArt / Adobe Stock