Oral clefts are one of the most common congenital malformations with prevalence rates of 1.5 per 1,000 births. The etiology of oral clefts remains unknown. Oral clefts are likely of multifactorial etiology, involving both genetic predisposition and environmental factors. Evidence also exists that specific nutritional factors may play a role in the etiology of oral clefts. Periconceptional supplementation with folic acid has been clearly shown to prevent the occurrence of neural tube defects. This is an important public health issue and provides further impetus into this line of investigation. The most efficient study design for assessing risk factors associated with rare diseases, such as congenital anomalies, is the case control design. This study will investigate the accuracy of the retrospective approach of data collection by determining the reproducibility of self reported information before and after pregnancy in 250 women. Specifically, this study will examine the reproducibility of self reported information of dietary factors, medication and tobacco use collected at two times: l.prior to the sixteenth week of pregnancy (at the time that women present for prenatal care) and 2.within six months after pregnancy. The reproducibility of dietary factors will be assessed by comparing mean values and by calculating correlation coefficients. The agreement of reporting of the frequency of use of vitamin supplements and medications will be evaluated by measuring percent agreement and use of the Kappa statistic between the two reports. Time at interview will be controlled for in these analyses. The results of this investigation should contribute significantly to the design and development of research of reproductive epidemiology.
