Congenital Anomaly Rate

Pregnancy and Before

The term congenital anomaly refers to any physiological or structural abnormality that is present at the time of birth. More than 3,000 congenital anomalies have been identified, such as neural tube defects, heart and circulatory system defects, cleft palate or lip, and Down Syndrome. These data come from the Canadian Congenital Anomalies Surveillance System.

The trends in congenital anomaly (CA) rates are different for different types of anomalies. The overall congenital anomaly rates for Simcoe Muskoka and Ontario have fluctuated between 450 and 600 CA’s per 10,000 population between 1974 and 2006.

The introduction and extensive use of prenatal diagnosis and pregnancy termination for serious congenital anomalies has had a significant impact on infant mortality, congenital anomaly and therapeutic abortion rates. Other interventions such as prenatal care and improvements in technology that enable surgeons to correct the anomalies in utero may contribute to declines in CA rates.

Neural Tube Defect Rate

Neural tube defects (NTD) are birth defects of the brain and spinal cord. NTD rates are the number of NTD's per 10,000 births in a population per year. These conditions can be prevented with folic acid supplementation prior to and during pregnancy. For more information on folic acid use during pregnancy in Simcoe Muskoka, please see the HealthSTATS page on folic acid supplementation. For more information on pregnancy and health, please visit the health unit’s website on health before pregnancy.

Figure 1 below shows the number of neural tube defects (NTD) per 10,000 births in Simcoe Muskoka and Ontario between 1974 and 2006. Both rates have decreased significantly during this time period.

In 1998, fortification of a variety of cereal products with folic acid became mandatory in Canada, which resulted in further reduction in the rate of neural-tube defects across the country (1). The Simcoe Muskoka NTD rate has more peaks and valleys than the Ontario rate because it is based on smaller numbers and thus has more variability.

Figure 1