Developmental Dysplasia of the Hip Is Not Associated with Breech Presentation in Preterm Infants

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.

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.

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.

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.

· 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..