Table 2. Analysis of Potential Antenatal and Perinatal Risk Factors for Late-Diagnosed Hip Dislocation.
| Risk Factor | Children, No.a | Children With Hip Dislocation | Control Children | Difference (95% CI) | Adjusted Odds Ratio (95% CI)b |
|---|---|---|---|---|---|
| Body weight, mean (SD), kgc | 101 | 67.2 (12.6) | 67.9 (12.6) | –0.71 (–3.3 to 1.9) | NA |
| Length, mean (SD), cm | 105 | 166 (6.3) | 166 (6.3) | –0.16 (–1.4 to 1.1) | NA |
| BMI, mean (SD), kg/cm2c | 99 | 24.3 (4.2) | 24.5 (4.2) | –0.23 (–1.1 to 0.6) | NA |
| Body weight at delivery, mean (SD), kg | 42 | 84.6 (15.1) | 82.4 (15.1) | 2.2 (–2.6 to 7.0) | NA |
| BMI at delivery, mean (SD)d | 38 | 30.5 (5.3) | 29.7 (5.3) | 0.82 (–1.0 to 2.6) | NA |
| Age, y | 114 | 30.8 (5.2) | 30.5 (5.2) | 0.3 (–0.7 to 1.3) | NA |
| Pregnancy, mean (SD), d | 114 | 275 (13.0) | 278 (13.0) | –3.1 (–0.6 to –5.6) | 1.03 (0.86 to 1.23) |
| Birth weight, mean (SD), g | 114 | 3440 (571.8) | 3459 (571.8) | –19 (–129 to 91) | NA |
| Body length at birth, mean (SD), cm | 113 | 49.5 (2.4) | 50.0 (2.4) | –0.53 (–0.07 to –0.99) | 0.86 (0.76 to 0.98) |
| Head circumference, mean (SD), cm | 107 | 34.6 (1.6) | 34.7 (1.6) | –0.05 (–0.37 to 0.27) | NA |
| Apgar score, mean (SD), min | |||||
| 1 | 112 | 8.6 (1.3) | 8.7 (1.3) | –0.07 (–0.33 to 0.18) | NA |
| 5 | 112 | 9.7 (0.9) | 9.7 (0.9) | –0.02 (–0.19 to 0.15) | NA |
| 10 | 112 | 9.9 (0.7) | 9.9 (0.7) | 0.03 (–0.11 to 0.17) | NA |
| Chronic disease, No./total No. (%)e | NA | 15/114 (13.2) | 99/1140 (8.7) | 4.5 (–1.1 to 10) | 1.57 (0.78 to 3.16) |
| Smoking, No./total No. (%)f | |||||
| Previous 3 mo | NA | 15/108 (13.9) | 181/1071 (16.9) | –3.0 (–10 to 4.4) | NA |
| First visitc | NA | 3/108 (2.8) | 92/1072 (8.6) | –5.8 (–11 to –0.4) | 0.16 (0.04 to 0.70) |
| Weeks 30-32 | NA | 4/104 (3.8) | 63/1042 (6.0) | –2.2 (–6.9 to 2.5) | NA |
| Snuff use, No./total No. (%) | |||||
| Previous 3 mo | NA | 4/108 (3.7) | 29/1071 (2.7) | 1.0 (–2.3 to 4.3) | NA |
| First visitc | NA | 2/108 (1.9) | 16/1072 (1.5) | 0.4 (–2.1 to 2.8) | NA |
| Weeks 30-32 | NA | 1/106 (0.9) | 5/1051 (0.5) | 0.5 (–1.0 to 1.9) | NA |
| Previous live birth, No./total No. (%) | NA | 57/114 (50.0) | 565/1140 (49.6) | 0.4 (–9.2 to 10) | NA |
| Breech delivery, No./total No. (%) | NA | 15/107 (14.0) | 60/1076 (5.6) | 8.4 (3.6 to 13) | 3.07 (1.34 to 7.02) |
| Previous cesarean delivery, No./total No. (%) | NA | 12/112 (10.7) | 95/1122 (8.5) | 2.2 (–3.2 to 7.7) | NA |
| Cesarean delivery, No./total No. (%) | NA | 36/114 (31.6) | 199/1140 (17.5) | 14 (6.6 to 22) | NA |
| Acute or elective surgical procedure, No./total No. (%)g | NA | 18/35 (51.4) | 84/170 (49.4) | 2.0 (–16 to 20) | NA |
| Forceps used, No./total No. (%) | NA | 1/114 (0.9) | 10/1140 (0.9) | 0 (–1.8 to 1.8) | NA |
| Suction bell used, No./total No. (%) | NA | 10/114 (8.8) | 95/1140 (8.3) | 0.4 (–4.9 to 5.8) | NA |
| Multiple pregnancy, No./total No. (%) | NA | 4/114 (3.5) | 35/1140 (3.1) | 0.4 (–2.9 to 3.8) | NA |
| High or low BMI, No./total No. (%)c,h | NA | 43/99 (43.4) | 446/1011 (44.1) | –0.6 (–11 to 9.6) | NA |
| Small for gestational age, No./total No. (%) | NA | 1/110 (0.9) | 20/1103 (1.8) | –0.9 (–3.5 to 1.7) | NA |
| Large for gestational age, No./total No. (%) | NA | 9/110 (8.2) | 39/1103 (3.5) | 4.6 (0.8 to 8.5) | 3.59 (1.30 to 9.95) |
Abbreviations: BMI, body mass index (calculated as weight in kilograms divided by height in meters squared); NA, not applicable.
Number of matching sets in each analysis for continuous variables.
Adjusted odds ratios including variables yielding P < .20 but excluding body weight (a priori) because of collinearity with BMI and cesarean delivery (in stepwise analysis) because of collinearity with breech presentation.
Measurement at first visit to maternal health care unit, typically at pregnancy weeks 8 to 10.
Calculated as weight in kilograms divided by height in meters squared.
Ongoing or previous chronic disease.
Smokers (1-9 cigarettes per day and >9 cigarettes per day pooled together) compared with nonsmokers.
Data on acute or elective surgical procedure not specified in 30 cases.
Mothers who had low (<20) or high (>25) compared with normal (20-25) BMI.