Urquia, a scientist at Toronto’s St. Michael’s Hospital, studied 6,375 new mothers and found that women living in common-law arrangements were about twice as likely as married women to experience either violence from their partner, substance abuse or postpartum depression. Single, nevermarried women were more than three times as likely to experience at least one of the three negative outcomes.

At least one of postpartum depression, substance abuse and partner abuse was reported by 10.6 per cent of married women. Twenty per cent of co-habiting but unmarried women fell into one of the three negative psychosocial conditions. For single, never married women, 35 per cent report experiencing one or more of the three problems.

The worst result was reserved for women who had separated or divorced during the 12 months before they gave birth. For this group, 67 per cent reported one or more of partner abuse, substance abuse and postpartum depression. This is information that doctors should take into account, Urquia told The Catholic Register.

“When a woman goes for her first prenatal visit it is probably important to know whether this woman is classified as married or co-habiting or single,” he said. “If those questions aren’t asked there is probably a missed opportunity to intervene and provide support and counselling.”

There is a self-selecting effect when it comes to marriage versus co-habiting or single motherhood, said Urquia. Women with higher incomes, better educations and greater opportunities are more likely to be married than living common law and the differences in class and status usually translate into better health outcomes. Urquia’s study also found that immigrant women were more likely to be married than women born in Canada.

Once these factors are taken into account the gaps narrow, but there are still significant differences when it comes to partner abuse, substance abuse and postpartum depression, Urquia said.

“Our interpretation of this effect that is not due to other factors is because of the greater commitment that marriage implies,” he said. “There is a commitment to a life-long relationship and family formation.”

Studies of health outcomes for the married and unmarried is limited by a lack of reliable data, said Urquia. Most surveys lump common law with married.
Among common-law couples, the psycho-social indicators improve the longer the couple has been together, with best results associated with couples who have been living together more than five years.

Urquia didn’t set out to prove that marriage is better for women.

“That is what the study is showing. It’s not that that is our purpose to show that,” he said. “We asked the question about what is the difference and that is what it is showing.”