Objective: To assess variations in seasonality and regional distribution of orofacial clefts in babies born in Zambia.

Design: A retrospective chart review was done using records of all cleft procedures performed by the only plastic surgeon in Zambia (G.J.). Delivery data from the University Teaching Hospital (UTH) were also examined to estimate the birth prevalence of orofacial clefts (55,108 live births between 2001 and 2005).

Patients: All cleft patients operated in Zambia from 2000 to 2006 (413 patients).

Results: A low birth prevalence of clefts (1/4239 live births) was found using UTH delivery data. Surgical data showed no difference for the frequency of one gender over another overall (M:F ratio is 1.04; p ?=? .70). More bilateral clefts occurred in cleft lip and palate (CLP) patients than in cleft lip (CL) patients (p < .01), and more unilateral left-sided clefts occurred in CL than in CLP patients (p ?=? .03). The data reflected seasonal variation in month of birth of cleft lip with or without cleft palate (CL±P) patients (p < .01), with a peak in April and May and more births in March through August (57.2%) than in September through February (42.8%). There was regional variation in cleft births among the nine Zambian provinces (p < .01).

Conclusions: This study shows seasonal variation in clefts that may be explained, at least in part, by environmental factors affecting the development of CL±P. Access to treatment is likely the major determinant of regional disparity in clefts. These results provide a basis for further epidemiological studies of orofacial clefts in Zambia.