London, Nov 16 (IANS): Having kids, the main purpose of matrimonial relationships, can bring in greater strains in romantic relationships than illness of partners, a new study suggests.

The study looked at the relationship quality of 721 couples in Switzerland over a period of thirteen years.

"Transition to parenthood is associated with a higher degree of closure of the couple, as well as greater differentiation of functional roles," said researcher Manuela Schicka from the University of Geneva in Switzerland in an official statement.

Schicka, who conducted the research as part of her PhD thesis, explained that women often abandon or substantially reduce their participation in the labour market once they become a mother, because of lack of institutionalised child care facilities. This also generates a great deal of frustration.

On the other hand, illness and accidents are seen as linked to bad luck and not personal responsibility.

There is therefore less grief and bitter thoughts between partners when the latter occur, Schicka stated.

The study also found that transition to retirement succeeds in reuniting couples at an age that is generally not perceived as the most romantic one.

The research demonstrated that while the various styles of conjugal interactions generally remain stable along the life course, some critical life events and transitions weigh much more on relationship quality than others, sometimes in unexpected ways.