Quebec study says tobacco a possible factor

A story by Francine Kopun in the National Post Nov. 24, 2004 revealed that married women have healthier babies than women living in common-law relationships. The source for her report was research by Statistics Canada.

A study of registered births done in Quebec from 1990 to 1997 found that women in common-law unions are 14% more likely to give birth before term, 18% more likely to have babies who are small for their gestational age, and 21% more likely to deliver babies of low birth weight. What's more, their babies have a 7% greater chance of dying within a month of birth and a 23% greater chance of dying within a year of birth. Overall, the risks to a baby's health are about 20% greater if the mother is living common-law and not married, according to Russell Wilkins, a senior analyst with the Health Analysis and Measurement Group at Statistics Canada, who was a lead author of the study.

The figures were adjusted for the mother's age, education, language and community size.

"It's not as inconsequential as it might appear," Mr. Wilkins said of the differences in the health of babies. "They're not large, but they apply to a lot of people. That's why they're important."

The prevalence of births to mothers living common-law in Quebec rose from 20% to 44% 1990 to 1997. A year later, in 1998, the total number of births to common-law mothers had exceeded the number of births to married moms.

Tobacco use was a possible contributing factor, said Mr. Wilkins. The prevalence of smokers among Quebec women aged 15-44 was 32% for married women, but 40% for those in common-law relationships. However, researchers calculated that smoking would only account for about 3% of the difference in the rate of pre-term births. They speculated that another possible cause could be greater stress in common-law relationships—some studies have shown higher separation rates and higher rates of physical abuse among common-law unions.

The findings met with surprise and even derision from women in Quebec.

Professor Rod Beaujot, who teaches sociology at the University of Western Ontario, speculated that people who marry may possess traits that produce healthier children: "I suspect that the greater amount of planning that's associated with marriage carries forward to other things… in terms of pre-natal visits and the various planning that goes into a birth," he said.

Dr. Michael Kramer of the department of epidemiology and biostatistics at McGill University—another of the researchers on the study—said he thought they would find that with common-law relationships becoming so popular in Quebec and so socially acceptable, any disparities would have disappeared over time.

Although no adjustment in the data could be made for income, because that information does not appear on birth certificates, adjustments were made for education, which is closely tied to income. The differences were above and beyond what could be explained by slight differences in education and income, Dr. Kramer said.

The study also found that children of women in common-law relationships were healthier than children of single moms. Babies born to single moms who did not identify a father on the birth certificate suffered the most ill effects of all.

The results of the study, called Disparities in Pregnancy Outcomes According to Marital Status and Cohabitation Status, were published in the professional journal Obstetrics and Gynecology. The study was a collaboration of Statistics Canada, McGill University and the Fetal and Infant Health Study Group of the Canadian Perinatal Surveillance System, funded by Health Canada.

While recognizing that not all families can fit into the normal model of the intact family—and acknowledging that other household formulations often need help—the CHP has long contended that the most important public policy objective for governments is to strengthen the married, two-parent family. This study reinforces that goal, in terms of the most important criterion for evaluating families: "What's best for the children?"