Changes in the registration of stillbirths < 500 g in Canada, 1985–95

Abstract

We assessed recent temporal trends in the registration of stillbirths in Canada, with particular regard to stillbirths < 500 g. Data from the Statistics Canada live birth and stillbirth databases for the period 1985-95 were used for the study. The primary analysis was restricted to data from 10 of the 12 provinces and territories of Canada. Data from Newfoundland were excluded because birthweight distributions were not available prior to 1990, and data from Ontario were excluded because of concerns about data quality. The proportion of stillbirths < 500 g increased by 47% [95% confidence interval (CI) 32, 63%], from 12.7% of stillbirths with known birthweight in 1985-7 to 18.7% in 1993-5. Similarly, the rate of stillbirths < 500 g increased by 36% [95% CI 21, 53%], from 7.2 to 9.8 per 10,000 total births from 1985-7 to 1993-5. Similar increases in stillbirth rates were not observed in other low birthweight categories. Live births < 500 g increased 53% [95% CI 33, 77%], from 4.6 to 7.0 per 10,000 live births. Some provinces and territories had low rates of stillbirths < 500 g and no increasing trend, whereas other provinces showed higher rates and increases over time. These regional differences were consistent with differences in stillbirth definitions across the provinces and territories of Canada. Spatio-temporal comparisons of crude stillbirth rates are likely to be compromised unless differences and changes in birth registration practices are addressed.

Secular trends in congenital anomaly-related fetal and infant mortality in Canada, 1985-1996

“…Birth registration practices have also changed over the study period, as reflected by the dramatic rise in the registration of extremely premature live births [Howell and Blondel, 1994; Sachs et al, 1995; Sepkowitz, 1995; Joseph and Kramer, 1996] and stillbirths [Joseph et al, 1999]. Although the definition of a live birth did not change, the definition of a stillbirth (which included gestational age and/or birth weight criteria) changed slightly in some of the provinces and territories of Canada between 1985 and 1996 [Joseph et al, 1999]. Such minor changes cannot explain the gestational age‐dependent pattern of temporal change observed among congenital anomaly‐related fetal and infant deaths, however.…”

“…During the study period, most Canadian provinces and territories defined a stillbirth as a fetal death with a gestational age ≥ 20 weeks or a birth weight ≥ 500 g birth weight, while a few provinces/territories used a single birth weight (fetal death with a birth weight ≥ 500 g) or a single gestational age criterion (fetal death at a gestational age ≥ 20 weeks) [Joseph et al, 1999]. Some provinces changed their stillbirth definition from one of three definitions listed above to another during the study period (e.g., in 1994 Saskatchewan changed its definition of stillbirth from fetal death at a gestational age ≥ 20 weeks or a birth weight ≥ 500 g to fetal death at a birth weight ≥ 500 g).…”

Preterm birth, stillbirth and infant mortality among triplet births in Canada, 1985–96

“…As our data source did not identify triplet sets, we recreated sets using identifiers such as birth date, maternal age and province of residence (498 sets created for 1459 triplet births). During the study period, birth registration requirements in Canada meant that only fetal deaths ≥ 20 weeks gestation and/or ≥500 g birthweight were registered as stillbirths 26 …”

Trends in birthweight in the north of England

“…International comparisons show a mixed picture: reports from Norway and North America show a similar increase in low birthweight (Daltveit et al, 1999;Joseph et al, 1999;Branum & Schoendorf, 2002), but there has been no such increase reported for Sweden (Odlind et al, 2003) or Scotland (Fairley, 2005).…”