Trends in Canadian Birth Weights, 1971 to 1989: Studying weight trends in singleton births.

This paper outlines levels and trends in birth weights of singleton birth weights of singleton births in Canada between 1971 and 1989. It relates these birth weights to maternal age, marital status, and parity and to gestational age. From 1971 to 1989, the median birth weight of all singletons increased by 104g, or 3.1%. The proportion of low birth weight babies declined, probably contributing to improved infant mortality rates.