Prevalence of Developmental Dysplasia of the Hip in a Maternity Hospital in São Paulo, Brazil.

 To evaluate the prevalence of developmental dysplasia of the hip (DDH), that is, hips classified as Graf type-IIc or higher, among a sample of the population of newborns aged from 0 to 3 days of life, and to correlate the findings with the main risk factors described in the literature.  An observational, cross-sectional, prospective study on a sample of newborns at a Maternity Hospital School in the city of São Paulo, Brazil, to assess the prevalence of DDH diagnosed by the Graf method and verify its correlation with the risk factors.  A total of 678 newborns underwent hip ultrasound (1,356 hips). The prevalence of DDH was of 5.46%. The logistic regression analysis showed odds ratios (ORs) with statistical significance for the following parameters: white ethnicity (OR = 2.561; 95% confidence interval [95%CI]: 1.07 to 6.11); multiparity (OR = 3.50; 95%CI: 1.62 to 7.38), female gender (OR = 4.95; 95%CI: 1.86 to 13.13); and breech presentation (OR = 2.03; 95%CI: 1,01 to 4.11).  The prevalence of DDH in the sample was of 5.45% using ultrasound as a diagnostic method. This result is different from that of studies that assessed prevalence exclusively through physical examination (Ortolani maneuver). The main risk factors associated with a higher risk of developing DDH were newborns of the female gender, with breech presentation, firstborns, and of white ethnicity.