Stability of orofacial clefting rate in alberta, 1980-2011.

Objective : To determine the prevalence and trends of orofacial clefts in Alberta (Canada) over a 33-year period (1980 through 2011) and to determine whether the trends differ for subcategories of orofacial clefts for the period from 1997 through 2011. Design : A prevalence study based on the Alberta Congenital Anomalies Surveillance System, which has multiple sources of ascertainment, capability of verification, and an upper age limit of 1 year. Inclusion : All live born and stillborn babies and fetal deaths less than 20 weeks' gestation (including terminations of pregnancy) born in Alberta of mothers who reside in Alberta. Results and Conclusions : Rates for cleft lip with or without cleft palate and cleft palate only have been very stable over the 33-year period (1980 through 2011). These rates include all clefts (isolated, syndromes, recognizable conditions, chromosomal and multiple congenital anomalies). Ascertainment of fetal deaths less than 20 weeks' gestation began in 1997. There are trends for the 1997 through 2011 cohort with a marginally significant increase for cleft lip with or without cleft palate in the isolated category and a significant decrease for cleft palate, mainly in the associated groups. The impact of folic acid fortification and/or multivitamins/folic acid supplementation reports in the literature have shown no consensus with respect to a change in the prevalence of orofacial clefts. It is unclear whether folic acid fortification has had any impact in Alberta.