Seasonal variation in birth date of children with cleft lip

Abstract

Liability to neural tube defects is increased by maternal dietary deficiency, and children with neural tube defects show a possibly related seasonal variation in date of birth. Since maternal dietary insufficiency may also increase liability to cleft lip, with or without cleft palate (CLP), we wondered if children with CLP would also show a seasonal variation in birth date. The multifactorial‐threshold model predicts that any such effect would be more apparent in males than females, since CLP is more frequent in males. Month of birth was obtained from records of 598 children with CLP seen at The Montreal Children's Hospital between 1950 and 1996. Children with syndromes or associated malformations were excluded. There was a significant tendency for children with CLP to be born more often in the summer than in winter. The difference was greater in males than in females. The seasonal fluctuation in month of birth of children with CLP is consistent with the presence of an environmental factor increasing liability, with a maximal effect in November–December. This might be related, at least in part, to a seasonal fluctuation in maternal nutrition. The data support the prediction that analyzing the data for the sexes separately would amplify the effects of variation in liability for a multifactorial threshold trait that has a different frequency in males and females. This approach could be useful in the study of other gene‐environment interactions. Teratology 57:93–95, 1998. © 1998 Wiley‐Liss, Inc.

Ten-year experience of more than 35,000 orofacial clefts in Africa

“…It is reasonable to expect that orofacial clefts may show seasonal variations in date of birth based on factors such as maternal malnutrition and low intake of folic acid [33]. The present data showed the greatest number of patients born in January (12.97%) and the fewest born in December (5.25%) (Table 4) with a decline in numbers over the course of the year.…”

A review of seasonality of cleft births – The Brazil experience

“…7,11 According to this model, the malformations result from factors such as genetic predisposition and exogenous factors like maternal malnutrition, low intake of folic acid, teratogens including drugs and alcohol, viruses and maternal age. 1,8,12 There are studies which evaluated a seasonal influence on the occurrence of CL/P [13][14][15][16][17][18][19] and they considered that it was reasonable to expect that orofacial clefts may show seasonal variations due to indirect factors such as maternal malnutrition and low intake of folic acid, 13,15 and other direct factors such as temperature, intensity of ultraviolet light exposure, use of fertilizers and pesticides in agriculture and infectious disease cycles.…”

“…The environmental factors which were cited as being related to seasonality and oral cleft included maternal dietary deficiencies, in particular low folic acid intake, ultra violet light exposure, use of fertilizers and pesticides in agriculture and infectious disease cycles. 13,15,17 In this study, nonparametric tests did not show a seasonal difference, considering the month of births and seasons, between healthy individuals and cleft patients (p = 0.902 and p = 0.679, respectively). It was identified only a difference in births between the groups in January, however, was not significant.…”

“…Although the theory of a seasonal influence on the occurrence of NSCL/P is controversial, showing studies without variation, 5,16,19,20 studies by Fraser and Gwyn, 15 Elliot et al 13 and Krost and Schubert 17 proved an influence of seasonality on the aetiology of clefts. Moreover, there are no previous studies which dealt with this subject in a Brazilian population.…”

Seasonal variation in months of birth of patients with microtia in a Chinese population

“…In females there was an equal distribution of births throughout the year. Data on other malformations also show that males have greater seasonal variation in birth data, such as cleft lip [4]. As the birth peak time of Chinese infants shows little difference between the two genders, there should be other factors involved.…”