Table 1.
Characteristics of 1201 pregnant women according to bacterial vaginosis status at recruitment
| Characteristic
|
No (%)
|
Prevalence (proportion) of bacterial vaginosis among women
|
Relative risk (95% CI)
|
Age adjusted relative risk (95% CI)¶
|
|
|---|---|---|---|---|---|
| Women with characteristic
|
Women without characteristic
|
||||
| Age <25 (n=1201) | 150 (12.5) | 22.6 (34/150) | 13.3 (140/1051) | 1.7 (1.2 to 2.5)** | — |
| Afro-Caribbean or black African (n=1096) | 116 (11.1) | 33.6 (39/116) | 11.1 (109/980) | 3.0 (2.1 to 4.4)*** | 2.9 (2.0 to 4.2)*** |
| Social class 3 to 5† (n=1036) | 415 (40.0) | 16.5 (68/415) | 10.5 (65/621) | 1.6 (1.1 to 2.2)** | 1.5 (1.0 to 2.1)* |
| Single, widowed, or divorced (n=1095) | 94 (8.58) | 28.7 (27/94) | 11.6 (116/1001) | 2.5 (1.6 to 3.8)*** | 2.3 (1.5 to 3.7)*** |
| Previous oral contraception or none (n=1085) | 683 (62.9) | 14.8 (101/683) | 10.7 (43/402) | 1.4 (1.0 to 2.0) | 1.4 (1.0 to 2.0) |
| No previous pregnancies (n=1094) | 388 (35.5) | 11.1 (43/388) | 15.2 (107/706) | 0.7 (0.5 to 1.0) | 0.7 (0.5 to 1.0) |
| Smoked during this pregnancy‡ (n=786) | 117 (14.9) | 17.1 (20/117) | 10.8 (72/669) | 1.6 (1.0 to 2.6) | 1.4 (0.9 to 2.4) |
| Previous termination of pregnancy (n=1087) | 270 (24.8) | 21.9 (59/270) | 10.7 (87/817) | 2.1 (1.5 to 2.9)*** | 2.0 (1.5 to 2.8)*** |
| Previous miscarriage§ (if ever been pregnant n=700) | 225 (32.1) | 16.0 (36/225) | 14.9 (71/475) | 1.1 (0.7 to 1.6) | 1.1 (0.7 to 1.6) |
| Previous preterm birth at <37 weeks (if ever been pregnant n=700) | 39 (5.6) | 10.3 (4/39) | 15.2 (101/661) | 0.7 (0.3 to 1.8) | 0.7 (0.3 to 1.8) |
| Concurrent chlamydial infection (n=1199) | 29 (2.4) | 44.8 (13/29) | 13.8 (161/1170) | 3.3 (1.9 to 5.7)*** | 2.8 (1.6 to 5.0)*** |
*
P<0.05, **P<0.01, ***P<0.001.
†
For women who were unemployed or students, partner's social class was used when available.
‡
Questions on smoking were omitted from questionnaires at start of study.
§
13 women had had ⩾3 miscarriages.
¶
Adjusted for age <25 or ⩾25.