Table 1. Cohort description, pregnancy rate and associations with pregnancy incidence in HIV negative women (n = 438; 57 pregnancies).
| Independent Variables | Sample Characteristics (%) | Total pregnancies (n) | Time to follow-up (Person Years) | Rate per 100 person-years (No. pregnancies/wyrs) | Crude Hazard Ratio | p-value |
| Age | ||||||
| 18–20 years | 178 (40.6) | 18 | 0.9 | 19.9 | 1 | |
| 21–25 years | 185 (42.2) | 31 | 1.0 | 31.5 | 1.5 (0.8–2.7) | 0.144 |
| 26–35 years | 75 (17.1) | 8 | 0.4 | 20.5 | 0.9 (0.4–2.2) | 0.953 |
| Employment | ||||||
| Unemployed | 302 (68.9) | 38 | 1.5 | 24.6 | 1 | 0.866 |
| Employed | 136 (31.1) | 19 | 0.7 | 26.1 | 1.0 (0.6–1.8) | |
| Language Acculturation1 | ||||||
| English | 207 (47.4) | 24 | 1.1 | 21.5 | 1 | |
| Setswana | 133 (30.4) | 17 | 0.7 | 25.1 | 1.2 (0.6–2.2) | 0.653 |
| Mix of English and Setswana | 97 (22.2) | 16 | 0.5 | 33.3 | 1.6 (0.9–3.1) | 0.138 |
| Past pregnancy attempt in 3 months prior to enrolment2 | ||||||
| No | 312 (76.3) | 36 | 1.7 | 21.4 | 1 | 0.022 |
| Yes (Participant perceived either 1 or both partners in the relationship as trying to become pregnant) | 97 (23.7) | 18 | 0.4 | 40.7 | 1.9 (1.1–3.4) | |
| Parity3 | ||||||
| 0 or 1 live birth | 297 (84.6) | 41 | 1.5 | 27.9 | 1 | 0.382 |
| 2 or more live births | 54 (15.4) | 6 | 0.3 | 19.6 | 0.7 (0.3–1.6) | |
| Any use of hormonal contraception in the 3 months prior to enrolment4 | ||||||
| No | 272 (75.9) | 44 | 1.4 | 31.2 | 1 | 0.260 |
| Yes | 86 (24.0) | 7 | 0.4 | 18.7 | 0.6 (0.3–1.4) | |
| Any use of male or female condoms in 3 months prior to enrolment with main partner5 | ||||||
| No | 133 (39.8) | 18 | 0.7 | 26.1 | 1 | 0.874 |
| Yes | 201 (60.2) | 24 | 1.0 | 24.3 | 0.9 (0.5–1.8) | |
| Induced Abortion in the 3 months prior to enrollment6 | ||||||
| No | 412 (97.9) | 53 | 2.1 | 24.7 | 1 | 0.672 |
| Yes | 9 (2.1) | 2 | 0.1 | 34.5 | 1.4 (0.3–5.6) | |
| Self-reported symptoms, diagnosis or treatment of sexually transmitted infections in the 3 months prior to enrolment | ||||||
| No | 208 (47.5) | 21 | 1.2 | 16.9 | 1 | 0.001 |
| Yes | 230 (52.5) | 36 | 1.0 | 34.9 | 2.6 (1.5–4.6) | |
| Total number of sex partners in the 3 months prior to enrolment | ||||||
| None | 20 (4.6) | 3 | 0.1 | 31.2 | 1 | |
| One | 327 (74.7) | 39 | 1.7 | 22.4 | 0.7 (0.2–2.1) | 0.479 |
| Two or more sex partners | 91 (20.8) | 15 | 0.4 | 34.1 | 1.0 (0.3–3.5) | 0.979 |
| Total number of new partners in 3 months prior to enrolment | ||||||
| No new sex partner | 308 (70.3) | 38 | 1.7 | 22.5 | 1 | 0.139 |
| 1 or more | 130 (29.7) | 19 | 0.6 | 32.3 | 1.5 (0.9–2.6) | |
| Total number of HIV positive partners7 | ||||||
| None | 122 (93.1) | 21 | 0.5 | 41.6 | 1 | 0.545 |
| 1 or more | 9 (6.9) | 3 | 0.1 | 57.8 | 1.5 (0.4–4.9) | |
| Gender Roles Beliefs* | ||||||
| Progressive View (1) | 70 (15.9) | 6 | 0.4 | 15.7 | 1 | 0.039* |
| Neutral View (2) | 303 (69.2) | 39 | 1.6 | 24.5 | 1.7 (1.0–2.7) | |
| Conservative View (3) | 65 (14.8) | 12 | 0.3 | 39.7 | 2.7 (1.1–7.1) | |
Footnotes: *Assuming a linear dose response where gender roles beliefs coded as progressive view = 1 neutral = 2, conservative view = 3 1n = 1 participant who spoke isiXhosa was removed from the analysis; 2This was the female participant's perception. n = 29 unknown, not applicable and missing data; 3n = 87 unknown, not applicable and missing data; 4n = 80 unknown, not applicable and missing data; 5n = 104 unknown, not applicable and missing data; 6n = 17 unknown, not applicable and missing data; 7n = 307 unknown, not applicable and missing data.