TABLE II.

Association of Perinatal Risk Factors and Radiographic Evidence of Acetabular Dysplasia at a Mean Age of 4.4 Years^*

Risk Factor	Odds Ratio (95% Confidence Interval)	P Value
Univariate analyses
Female sex	3.26 (1.31-8.15)	0.01
First-born child	0.88 (0.41-1.89)	0.74
Twin pregnancy	0.48 (0.11-2.05)	0.32
Vaginal delivery	1.18 (0.55-2.54)	0.67
First-degree family history	1.90 (0.64-5.62)	0.25
Breech presentation	1.07 (0.48-2.42)	0.86
Abnormal hip examination	2.60 (0.76-8.96)	0.13
Birth weight, per kg	0.74 (0.38-1.42)	0.36
Multivariate analysis†
Female sex	2.59 (1.04-6.46)	0.04
Twin pregnancy	0.49 (0.11-2.21)	0.35
First-degree family history	1.53 (0.32-7.43)	0.59
Abnormal hip examination	1.00 (0.97-1.03)	1
Birth weight in kg	0.66 (0.30-1.43)	0.29
Treatment	1.09 (0.11-10.65)	0.94

^*Acetabular index >2 standard deviations above normative values. Among 27 patients with this outcome, 3 (11%) had been treated in early infancy.

^†Adjusted for any treatment received in infancy.