Demographic and prenatal factors of patients with cleft lip and cleft palate. A pilot study

Cleft lip, or CL, and cleft palate, or CP, are common congenital abnormalities. Birth prevalence ranges from one in every 500 to 1,000 in the white population and one in every 2,000 births in the African-American population. Etiologic and genetic factors contributing to CL and CP development are unknown though extensive research has been conducted. The authors conducted this pilot study to investigate a study design that could allow for an evaluation of such etiologic factors by providing the required estimate of the projected magnitude of differences between cases and controls.

The authors obtained pregnancy history data from the mothers of 137 consecutive patients at the University of Pittsburgh Cleft Palate-Craniofacial Center. The authors investigated the differences between sex or cleft status and family history of clefts, birth order, maternal age at birth and first-trimester maternal smoking and alcohol consumption.

None of the factors showed any significant differences by sex or cleft type (P > or = .07) in the pilot data. Power estimates ranged from 12 to 71 percent. The sample size needed to obtain power of 80 percent would be 250 for variables with two categories and 480 for variables with three categories.

There is no evidence that the factors contribute to either sex or cleft status differences. Further investigations are needed, and they should include a larger, more diverse sample of at least 250 cases, a matched control group and a focus on mothers of newborns.

This study lays the groundwork for a better understanding of the etiology of CL and CP-common birth defects that present challenges for long-term dental management.