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

• Published in: Health promotion and chronic disease prevention in Canada Vol. 35; no. 5; pp. 79 - 84
• Main Authors: Liu, S, Rouleau, J, León, J A, Sauve, R, Joseph, K S, Ray, J G
• Format: Journal Article
• Language: English
• Published: Canada Public Health Agency of Canada 01-07-2015
• Subjects: Adult; Canada - epidemiology; Congenital Abnormalities - epidemiology; Congenital Abnormalities - etiology; diabetes mellitus, pre-pregnancy, congenital anomaly, birth defect, trends, population attributable risk percent; Diabetes Mellitus, Type 1 - complications; Diabetes Mellitus, Type 1 - epidemiology; Diabetes Mellitus, Type 2 - complications; Diabetes Mellitus, Type 2 - epidemiology; Digestive System Abnormalities - epidemiology; Female; Heart Defects, Congenital - epidemiology; Humans; Infant, Newborn; Live Birth - epidemiology; Musculoskeletal Abnormalities - epidemiology; Nervous System Malformations - epidemiology; Pregnancy; Pregnancy in Diabetics - epidemiology; Prevalence; Risk Factors; Urogenital Abnormalities - epidemiology; Canada; birth defect; diabetes mellitus; population attributable risk percent; congenital anomaly; trends; pre-pregnancy
• ISSN: 2368-738X; 2368-738X
• DOI: 10.24095/hpcdp.35.5.01

To examine the impact of pre-pregnancy diabetes mellitus (DM) on the population birth prevalence of congenital anomalies in Canada.
We carried out a population-based study of all women who delivered in Canadian hospitals (except those in the province of Quebec) between April 2002 and March 2013 and their live-born infants with a birth weight of 500 grams or more and/or a gestational age of 22 weeks or more. Pre-pregnancy type 1 or type 2 DM was identified using ICD-10 diagnostic codes. The association between DM and all congenital anomalies as well as specific congenital anomaly categories was estimated using adjusted odds ratios; the impact was calculated as a population attributable risk percent (PAR%).
There were 118,892 infants with a congenital anomaly among 2,839,680 live births (41.9 per 1000). While the prevalence of any congenital anomaly declined from 50.7 per 1000 live births in 2002/03 to 41.5 per 1000 in 2012/13, the corresponding PAR% for a congenital anomaly related to pre-pregnancy DM rose from 0.6% (95% confidence interval [CI]: 0.4-0.8) to 1.2% (95% CI: 0.9-1.4). Specifically, the PAR% for congenital cardiovascular defects increased from 2.3% (95% CI: 1.7-2.9) to 4.2% (95% CI: 3.5-4.9) and for gastrointestinal defects from 0.8% (95% CI: 0.2-1.9) to 1.4% (95% CI: 0.7-2.6) over the study period.
Although there has been a relative decline in the prevalence of congenital anomalies in Canada, the proportion of congenital anomalies due to maternal pre-pregnancy DM has increased. Enhancement of preconception care initiatives for women with DM is recommended.