New York, May 9 (IANS): Even couples who share household work relatively equally stop doing so after the arrival of the baby as the man withdraws from many of the chores that he used to do, new research has found.

The researchers found that after the baby's birth, women's workloads increased by two hours a day, while men's total working time each day increased by only about 40 minutes.

"Women ended up shouldering a lot more of the work that comes with a new baby, even though both men and women thought they added the same amount of additional work," said co-author of the study Claire Kamp Dush, associate professor of human sciences at the Ohio State University.

The results were especially surprising because before the baby was born, these couples were sharing household chores relatively equally.

"The birth of the child dramatically changed the division of labour in these couples," co-author of the study Jill Yavorsky from the Ohio State University noted.

"What was once a relatively even division of household work no longer looked that way," Yavorsky noted.

In all, 182 couples participated in this study. Participants in the study tend to have higher-than-average levels of education, both spouses have jobs and both spouses report their intention to keep working after the child is born.

The couples were studied twice - once during the third trimester of pregnancy and then again when their babies were about nine months old.

At both times, the couples separately completed a detailed time diary for one workday and one non-workday.

One explanation for women's increased post-parenthood workloads compared to men has been that they are spending less time at their paid jobs. But this study didn't find that.

Neither men nor women had significantly decreased the number of hours spent at their paid jobs, the results showed.

The study appeared in the Journal of Marriage and Family.