Objectives: The aim of the study is to (1) determine the incidence of developmental dysplasia of the hip (DDH) in preterm infants born prior to 35 completed weeks' gestation in a breech presentation, and (2) evaluate if the association between breech presentation and DDH in full-term infants holds for premature infants.
Study design: This study design comprises retrospective review of infants born between January 1, 2008, and December 31, 2017, at <35 weeks' gestation and admitted to the NICU. Infants had hip ultrasounds at 4 to 6 weeks' corrected age if they were born in a breech presentation with a stable hip examination. We excluded infants born in a presentation other than breech or vertex, had no documentation of presentation at birth, or if they died within the first year.
Results: We included 1,533 infants. Preterm infants <35 weeks' gestation born in the breech versus vertex position had an incidence of DDH of 0.47% (2/428) and 0.36% (4/1,105), respectively. There was no significant difference in the incidence of DDH between infants born in the breech versus vertex position (Chi-square and Fisher's exact tests). The sensitivity, specificity, and positive and negative predictive values of breech presentation in detecting DDH were 33, 72, 0.47, and 99.6%, respectively.
Conclusion: There is no association between breech presentation and DDH in preterm infants <35 weeks' gestation. Obtaining hip ultrasounds on preterm infants <35 weeks' gestation born in the breech presentation with a normal hip examination is not recommended.
Key points: · Breech position is a risk factor for DDH in term newborns.. · Preterm infants are often in the breech position until 37 weeks' gestation.. · This study shows that breech presentation is not a risk factor for DDH in preterm infants..
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