Nothing changes a couple’s relationship more than the birth of their first child. At a time of immense joy and love, couples struggle with an increase in daily chores, stress, sleep deprivation, sometimes depression and conflict. At a time when the child is at its most vulnerable, parents are experiencing high levels of stress.

Researchers from Penn State University interviewed 399 mums and dads every night over the first 10 months of their first child’s life. During each telephone interview, parents were asked for an estimate of time spent at work, on household chores, travelling, sleeping and exercising. They wanted to find out how the stresses and supports of each day affect parenting and their relationship with each other.

The study found that the more housework the husband did, the more arguments the couple had. Arguments were over the father not wanting to do the housework, inability to do it properly or wanting to spend the time doing something else.

Lauren and Matt Smith from Sydney have 12-week-old twin girls, Isla and Madeline. “The arguing that goes on is ridiculous,” says Lauren. “It could be over the tiniest things, like the washing up, how I expect him to wash up when he gets home from work,” she says.

The study found the more housework the husband did, the more intimate the mother felt, but there were more arguments.

Not surprisingly, they found the more sleep a mother got, the less irritable she was and the closer she felt to her child and husband. This was probably due to having more patience after a good night’s sleep. Expressing and bottle-feeding twins in the middle of the night took Lauren an hour and a half, which resulted in her feeling exhausted the next day. “Matt now gives the bottles and would be back in bed after 20 minutes,” says Lauren, which improved her sleep and relationship with her family.

If the father got a good night's sleep, he felt closer to his family the next day. But, when the father slept more on average, he reported less closeness with his family. The researches summed this up as possible depression. The mother wouldn’t get a chance to sleep in, so if she was depressed, she would have to soldier on.

Interestingly on days the father took time to exercise, the mother was happier, and they were more intimate. When the mother tried to take time to exercise, arguments were more likely to occur as the husband was left to mind the baby. Lauren agreed with this. “I try to go for a walk every day with the girls,” she says, “If I went out (to exercise alone) he would either need help or it would lead to an argument.”

Daily stresses of dealing with a distressed baby, chores and couple conflict affected men and women differently. “Nighttime is just hectic,” says Lauren. “We are trying to get dinner ready for ourselves, bath them, trying to put them down and we have clothes and crap everywhere,” she says. “Matt baths one while I look after the other. I feel he takes 15 minutes to bath each one. You have to get them in and out. There is so much to do.” The researchers found mothers accumulated the daily stress, leading to even higher levels of stress.

“All the mums turn into mum mode and they just know they have to deal with it, no matter what happens. They get their shit together and just deal with it. But dads don’t quite understand that, I don’t think they get it,” says Lauren.