To discuss the main risk factors and protecting factors of nonsyndromic cleft lip and palate(NSCL/P)in order to provide theoretical basis for the prevention of the occurrence of the disease.

A hospital-based 1 : 1 matched case-control study design was applied to this epidemiological study. There were 76 cases with nonsyndromic cleft lip and palate children who were selected from Department of Stomatology of Affiliated Hospital of WeiFang Medical College, People's Hospital of WeiFang, Heze Municipal Hospital and Yuhuangding Hospital of Yantai from September 2006 to september 2007 as collecting cases, and control cases were chosen from the same medical institution with the matched patients. Parents of patients and control cases were asked some questions about 42 possible influencing factors and the answers were filled in the questionnaire by investigators. To carry on the multivariate stepwise regression analysis in univariate conditional Logistic regression analysis foundation in order to discover risk factors.

There were 6 risk factors which were related to nonsyndromic cleft lip and palate in the model, maternal infectious (P= 0. 010), genetic family history(P= 0. 009), maternal disorder diet(P= 0. 007), birth order(P= 0. 004), maternal stress during the first trimester of pregnancy(P= 0. 000), father's education level(P= 0. 000).

Maternal infectious, genetic family history, maternal disorder diet, birth order and maternal stress during the first trimester of pregnancy are promoting factors of nonsyndromic cleft lip and palate, while father's education level is a protecting factor.