| N | n (%) | OR* (95% CI) | p Value | |
| Ever pregnant | ||||
| Ever | 1550 | 58 (3.7) | 1 | 0.52 |
| Never | 630 | 6 (1.0) | 0.6 (0.1 to 2.7) | |
| Pregnant in past year | ||||
| No | 1952 | 56 (2.9) | 1 | 0.87 |
| Yes | 228 | 8 (3.5) | 0.9 (0.4 to 2.0) | |
| Age at first pregnancy† (years) | ||||
| <20 | 231 | 14 (6.1) | 1 | p Value for trend 0.83 |
| 20–29 | 1185 | 41 (3.5) | 1.1 (0.5 to 2.2) | |
| 30–39 | 134 | 3 (2.2) | 0.8 (0.2 to 2.9) | |
| Main method of contraception‡ | ||||
| None | 505 | 16 (3.2) | 1 | 0.37 |
| Sterilised | 417 | 15 (3.6) | 0.9 (0.4 to 2.0) | |
| IUCD | 65 | 4 (6.2) | 2.9 (1.0 to 8.4) | |
| Condom | 144 | 2 (1.4) | 0.5 (0.1 to 2.3) | |
| Other | 354 | 13 (3.7) | 1.3 (0.6 to 2.7) | |
| Pregnant since previous round2§ | ||||
| No | 3943 | 62 (1.5) | 1 | 0.21 |
| Yes | 61 | 3 (4.9) | 2.4 (0.7 to 8.0) | |
| BV at start of period3–5 | ||||
| No | 3288 | 46 (1.4) | 1 | 0.38 |
| Yes | 624 | 14 (2.2) | 1.3 (0.7 to 2.5) | |
| BV currently3¶ | ||||
| No | 3364 | 42 (1.2) | 1 | <0.001 |
| Yes | 538 | 22 (4.1) | 2.7 (1.6 to 4.6) | |
| Candidiasis currently3–5 | ||||
| No | 3588 | 61 (1.7) | 1 | 0.28 |
| Yes | 313 | 3 (1.0) | 0.6 (0.2 to 1.8) |
BV, Bacterial vaginosis; IUCD, intrauterine contraceptive device; OR, odds ratio.
*Adjusted for ethnicity, toilet in home, tapwater in home, difficulty managing financially and household size.
†Among 1550 ever-pregnant women.
‡Among 1552 married women only.
§For these time-changing variables, the figures relate to time periods at risk (up to two per woman).
¶Restricted to the 1968 with adequate vaginal smears at follow-up.