People often say that having a second child doesn’t much add to the workload of parenting. There’s no steep learning curve: You already know how to make a bottle, install a car seat and when to call the pediatrician. And you’re already doing laundry, making lunches and supervising bath time—so throwing a second kid in the tub isn’t a big deal.

Except that it is. Having a second child doesn’t just mean attaching a second seat to your stroller. Adding a whole new person to your family is more complicated than that, and it’s okay to say that it is hard.

A study out of Australia disputes the popular idea that after making the transition from people to parents, making the jump from one child to two is easy. The researchers found that having a second child puts a lot of pressure on parents’ time and their mental health, and mothers bear the brunt of the burden.

When looking at heterosexual couples, the researchers found that before a first child is born both partners feel equal amounts of “time pressure,” but once the child is born, that pressure grows, more so for mothers than fathers.

Basically, parents feel psychological stress when they feel they don’t have enough time to do all they need to. One baby makes both parents feel more stress, but mom’s increase is more than dad’s. When a second baby comes, that time pressure doubles for both parents, and since mom already had more than dad, there’s now a gulf between them.

The researchers behind this study—Leah Ruppanner, Francisco Perales and Janeen Baxter—say that after a first child is born, a mother’s mental health improves, but after a second child, it declines.

Writing for The Conversation, the trio explains:

“Second children intensify mothers’ feelings of time pressure. We showed that if mothers did not have such intense time pressures following second children, their mental health would actually improve with motherhood. Fathers get a mental health boost with their first child, but also see their mental health decline with the second child. But, unlike mothers, fathers’ mental health plateaus over time. Clearly, fathers aren’t facing the same chronic time pressure as mothers over the long-term.”

The researchers say that even when mothers reduce their work time, the time pressure is still there and that “mothers cannot shoulder the time demands of children alone.”

Adding a second child to the family isn’t just a matter of throwing a few more socks in the laundry: It means a schedule that is already stretched is now filling up with twice as many appointments, twice as many school functions. Mothers only have 24 hours in the day, and as much as we wish we could add a couple extra hours per child, we can’t.

Time simply can’t change to help us, but society can. As the researchers noted, when time pressure is removed, motherhood actually improves mental health.

We love our lives, we love our kids, we love parenting, but there is only so much of our day to go around.

Ruppanner, Perales and Baxter suggest that if society were to help mothers out more, our mental health (and therefore our children’s wellbeing as well) would improve even after two or three kids. “Collectivising childcare – for example, through school buses, lunch programs and flexible work policies that allow fathers’ involvement – may help improve maternal mental health,” the researchers explain, adding that “it is in the national interest to reduce stressors so that mothers, children and families can thrive.”

Whether you’re talking about Australia or America, that last bit is so true, but this research proves that the myth about second-time parenthood isn’t. Even if you already have the skills and the hand-me-downs, having a second child isn’t as easy as it is sometimes made out to be.

We can love our children and our lives and still admit when things aren’t easy.

[This post was first published December 18, 2018.]