Not seeking yet trying long-acting reversible contraception: a 24-month randomized trial on continuation, unintended pregnancy and satisfaction

Abstract

Objectives: To measure the 24-month impact on continuation, unintended pregnancy and satisfaction of trying long-acting reversible contraception (LARC) in a population seeking short-acting reversible contraception (SARC).

Study design: We enrolled 916 women aged 18-29 who were seeking pills or injectables in a partially randomized patient preference trial. Women with strong preferences for pills or injectables started on those products, while others opted for randomization to LARC or SARC and received their methods gratis. We estimated continuation and unintended pregnancy rates through 24months. Intent-to-treat principles were applied after method initiation for comparing incidence of unintended pregnancy. We also examined how satisfaction levels varied by cohort and how baseline negative LARC attitudes were associated with satisfaction over time.

Results: Forty-three percent chose randomization, and 57% chose the preference option. Complete loss to follow-up was<2%. The 24-month LARC continuation probability was 64.3% [95% confidence interval (CI): 56.6-70.9], statistically higher than SARC groups [25.5% (randomized) and 40.0% (preference)]. The 24-month cumulative unintended pregnancy probabilities were 9.9% (95% CI: 7.2-12.6) (preference-SARC), 6.9% (95% CI: 3.3-10.6) (randomized-SARC) and 3.6% (95% CI: 1.8-6.4) (randomized-LARC). Statistical tests for comparing randomized groups on unintended pregnancy were mixed: binomial at 24-month time point (p=.02) and log-rank survival probabilities (p=.14 for first pregnancies and p=.07 when including second pregnancies). LARC satisfaction was high (80% happy/neutral, 73% would use LARC again, 81% would recommend to a friend). Baseline negative attitudes toward LARC (27%) were not clearly associated with satisfaction or early discontinuation.

Conclusions: The decision to try LARC resulted in high continuation rates and substantial protection from unintended pregnancy over 24months. Despite participants' initial desires to begin short-acting regimens, they had high satisfaction with LARC. Voluntary decisions to try LARC will benefit large proportions of typical SARC users.

Implications: Even women who do not necessarily view LARC as a first choice may have a highly satisfying experience and avoid unintended pregnancy if they try it.

Trial registration: ClinicalTrials.gov NCT01299116.

Keywords: Acceptability, contraceptive continuation; Adherence; Long-acting reversible contraception; Randomized; Unintended pregnancy.

Figure 1.. Participant flow in study

LARC = Long-acting reversible contraception (IUDs and implants) SARC = Short-acting reversible contraception (oral contraceptives and DMPA) * excluded from further analysis because of insufficient numbers for comparison to randomized LARC group ** all participants who had some follow-up information for analysis (n=11 completely lost to follow-up) *** did not experience endpoint at time of last contact and did not have 24-month information

Figure 2.. Cumulative crude probability of continuation by study cohort

* Randomized groups (primary comparison): P<0.0001 Based on logrank tests ** SARC groups (secondary comparison): P=0.0013 Based on logrank tests

Figure 3.. Cumulative crude probability of unintended pregnancy by study cohort

Based only on first unintended pregnancies. * SARC groups (Secondary comparison): P=0.25 (logrank test), P=0.06 (binomial test at 24-month timepoint) ** Randomized groups (primary comparison): P=0.14 (logrank test), P=0.02 (binomial test at 24-month timepoint)