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

Abstract

Prenatal diagnosis of major congenital anomalies and subsequent termination of affected pregnancies has been widely available as part of routine obstetric care in recent years. In this study, vital statistical data on stillbirths, live births, and infant deaths were used to examine secular trends in gestational age-specific and category-specific fetal and infant mortality due to congenital anomalies in Canada (excluding Ontario and Newfoundland) from 1985-1996. Comparisons of the rates between 1985-1987 and 1994-1996 were made using relative risks and 95% confidence intervals (CI). The overall fetal mortality rate due to congenital anomalies increased significantly, from 68.0 per 100,000 total births in 1985-1987 to 78.6 per 100,000 total births in 1994-1996, while the overall infant mortality rate due to congenital anomalies decreased significantly over the same period, from 2.47 to 1.79 per 1,000 live births. The fetal death rate due to congenital anomalies at 20-21 weeks of gestation increased approximately five-fold (relative risk [RR] = 4.83, 95% CI = 3.28-7.11) from 4.5 to 21.5 per 100,000 fetuses at risk, while the rate at 37-41 weeks decreased by 30% (RR = 0.70, 95% CI = 0.50-0.97). Fetal death rates among pregnancies at 20-25 weeks of gestation increased in all categories of congenital anomaly except anencephaly and respiratory system anomalies. Congenital anomaly-related fetal and infant deaths have increased at early gestation but declined at later gestation in Canada. These changes suggest an increase in prenatal diagnosis and selective termination of pregnancies with congenital anomalies in recent years.

Effect of Folic Acid Food Fortification in Canada on Congenital Heart Disease Subtypes

“…This proxy variable includes a substantial and increasing fraction of late-pregnancy terminations for prenatally diagnosed congenital anomalies. 5,26,27,36,37 Data were stratified according to geographic area of maternal residence (14 strata: 5 regions in Ontario; 2 in Alberta; 2 in British Columbia; 1 for Saskatchewan, New Brunswick, and Newfoundland each; 1 for Nova Scotia and Prince Edward Island combined; and 1 for the Northwest Territories, Yukon, and Nunavut combined) and year (9 strata from 1990–1998, 13 strata from 1999–2011), resulting in 126 strata for the prefortification period and 182 strata for the post–food fortification period. Goodness of fit of the Poisson regression model was assessed with deviance statistics and the Pearson χ 2 test, and variance estimates were corrected for overdispersion through appropriate scaling.…”

Impact of pre-pregnancy diabetes mellitus on congenital anomalies, Canada, 2002–2012

“…[1][2][3] Congenital anomalies may also necessitate surgery and special care for several years after birth. 4 Children of women with pre-pregnancy type 1 and type 2 diabetes mellitus (DM) are at 2 to 10 times higher risk for congenital anomalies, especially cardiovascular and central nervous defects, compared with the nondiabetic population.…”

Association Between Maternal Chronic Conditions and Congenital Heart Defects

“…[1][2][3][4] CHDs constitute the most common congenital anomaly subgroup among newborns and have emerged as one of the most important causes of infant mortality. [5][6][7][8] Furthermore, CHDs have a significant impact on child and adult morbidity and disability. [7][8][9][10][11] Clinical Perspective on p 589…”