Table 1.
Characteristics in early pregnancy of the women included in the study
| Characteristic | n | Mean (S.D.) or proportion (%) |
|---|---|---|
| Age (yr) |
195 |
27.8 (4.6) |
| Weight (kg) |
188 |
63.7 (8.7) |
| Height (m) |
187 |
1.66 (0.06) |
| Body mass index (kg/m2) |
187 |
23.0 (2.9) |
| No cigarette smoking (%) |
151/195 |
77 |
| Pregnant for the first time (%) |
79/194 |
41 |
| Nulliparous (%) |
116/194 |
60 |
| Number of previous pregnancies |
194 |
0.9 (0.9) |
| Number of previous deliveries |
194 |
0.5 (0.7) |
| Time since previous delivery (yr) |
78 |
3.3 (0.4) |
| Previous back pain, not during pregnancy (%) |
113/195 |
58 |
| Back pain in previous pregnancy (%) | 46/115 | 40 |