Impact of changing age and parity distributions of mothers on perinatal mortality in Sweden, 1953-1975.

A study was made on how the shift in the age and parity distribution of mothers affected the perinatal mortality in Sweden between 1953-55 and 1973-75. During these years the overall perinatal mortality rate fell from 29 to 13 per 1 000 births. The authors used the specific perinatal mortality rates by the mother's age and infant's birth order in 1973-75 to calculate what the overall perinatal mortality rate would have been with the age and parity distributions of mothers in 1953-55 and 1963-65. They conclude that only 1.4 of the 16 per 1 000 decline in perinatal mortality could be attributed to the shift in the mother's age and parity distribution.