Table 3.
Cumulative crude probability of contraceptive method continuation and unintended pregnancy within 24 monthsa
| Preference-SARC (n=522) | Randomized-SARC (n=195) | Randomized-LARC (n=177) | |
|---|---|---|---|
| Number of discontinuing original method | 300 | 142 | 62 |
| Person-years | 654.5 | 225.2 | 274.2 |
| Probability of method continuation (95% CI)b | 40.0 (38.9–41.1) | 25.5 (22.3–28.7) | 64.3 (56.6–70.9) |
| OC only: | OC only: | IUD only: | |
| 45.0 (40.1–49.8) | 31.1 (23.7–38.7) | 65.0 (55.8–72.7) | |
| DMPA only: 18.4 (14.3–22.5) | DMPA only: 9.5 (5.0–14.0) | Implant only: 62.6 (47.9–74.3) | |
| Combining SARC preference and randomized cohorts | OC: 41.3 (37.2–45.4) DMPA: 15.4 (12.3–18.5) |
||
| Reason for method discontinuation [N (%)] | |||
| Wanted to get pregnant | 19 (3.6) | 6 (3.1) | 5 (2.8) |
| Not having sex | 39 (7.5) | 11 (5.6) | 0 (0.0) |
| Side effects | 67 (12.8) | 31 (15.9) | 46 (26.0) |
| Inconvenience of getting more | 34 (6.5) | 18 (9.2) | 0 (0.0) |
| Cost | 27 (5.2) | 7 (3.6) | 0 (0.0) |
| Got pregnant accidentally | 9 (1.7) | 3 (1.5) | 0 (0.0) |
| Forgot to redosec | 40 (7.7) | 20 (10.3) | 0 (0.0) |
| Other | 19 (3.6) | 10 (5.1) | 4 (2.3) |
| IUD expulsion | 0 (0.0) | 0 (0.0) | 6 (3.4) |
| No reasons given | 46 (8.8) | 36 (18.5) | 1 (0.6) |
| Did not discontinue | 222 (42.5) | 53 (27.2) | 115 (65.0) |
| Actions taken after discontinuing original methodd | |||
| Restarted original method | 71 (26.2%) | 29 (22.1%) | 0 (0.0%) |
| Switched to other short-acting method | 96 (35.4%) | 48 (36.6%) | 45 (72.6%) |
| Switched to LARC (or different LARC) | 22 (8.1%) | 25 (19.1%) | 3 (4.8%) |
| Declared no method being used | 74 (27.3%) | 26 (19.9%) | 14 (22.6%) |
| No information reported or missing | 8 (3.0%) | 3 (2.2%) | 0 (0.0%) |
| Number of pregnancies | |||
| Intended | 18 | 5 | 3 |
| Unintendede | 47 | 13 | 6 |
| Person-years | 908.1 | 359.9 | 334.9 |
| Probability of unintended pregnancy (95% CI)f | 9.9 (7.2–12.6) | 6.9 (3.3–10.6) | 3.6 (1.8–6.4) |
| Combining SARC preference and randomized cohorts | OC: 8.5 (6.1–10.8) DMPA: 11.5 (6.0–18.0) |
||
OC = oral contraceptives.
Eleven participants were completely lost to follow-up and are not included.
Between randomized groups: p<.0001; between SARC groups: p=.0013.
Includes forgot to take the pills or get a new injection, forgot to get new pill packs and misplaced pill packs.
Includes only participants who had discontinuation events unrelated to subsequent pregnancy to better evaluate immediate contraceptive actions [preference-SARC (n=271), randomized-SARC (n=131), randomized-LARC (n=62)].
Not included are five repeat unintended pregnancies (three in preference-SARC and two in randomized-SARC).
Based only on first unintended pregnancies. Between randomized groups: p=.14 (log-rank test) and p=.02 (binomial test at 24-month time point); between SARC groups: p=.25 (log-rank test) and p=.06 (binomial test at 24-month time point).