Circular distribution-based analyses of conception month of oral clefts cases of Guangdong Province

Objective To investigate the distribution of the conception month in oral clefts cases of Guangdong Province. Methods The statistical year of oral clefts cases conception date is regarded as a circle. The conception month clustering of oral clefts cases from the Birth Defects Monitoring Network of Guangdong Province during 2016-2017 by circular distribution method were analyzed. Results From 2016 to 2017, a total of 3, 748, 435 perinatal infants were monitored in Guangdong Province, 5591 cases with cleft lip or palate were detected, including 3137 male infants, 2309 female infants, 145 infants with unidentified gender. Excluding unidentified gender cases, 1368 cases with cleft lip, 913 cases with cleft palate, 3165 cases of cleft lip with palate. Oral clefts cases are conceived with a time aggregation (α = 67.33, P<0.001) , which is in the Early March. The time aggregation of cleft lip and cleft lip with cleft palate conception was in late February and mid-March, respectively. The time aggregation of cleft palate (CP) has no statistical significance. The conception time of female cleft cases have statistical significance of time aggregation, male cleft cases have no conception time aggregation. Conclusions The conception month of oral clefts cases in Guangdong Province has time aggregation. Cleft palate may have a different etiology model with cleft lip and cleft lip with cleft palate. The incidences of female cleft fetuses lip are more susceptible to conception time. Conception in spring should be alert to the occurrence of oral clefts. Key words: Clefts lip; Clefts palate; Conception month; Circular distribution