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BACKGROUND: International guidelines recommend placement of intrauterine devices immediately after second trimester medical abortion, but evidence concerning the optimal time for intrauterine device placement is lacking from clinical trials.

OBJECTIVE: We aimed to investigate effectiveness, safety, and acceptability of intrauterine device placement within 48 hours, compared with placement at two to four weeks after second trimester medical abortion. We hypothesized that intrauterine device placement within 48 hours would be superior compared with placement at two to four weeks after the abortion, in terms of the proportion of intrauterine device use after six months, with maintained safety and acceptability.

STUDY DESIGN: In this open-label, randomized, controlled, superiority trial, we recruited participants at eight abortion clinics in Sweden. Eligible participants were ≥18 years, requesting medical abortion with gestation ≥85 days and opting for use of a post abortion intrauterine device. Participants were randomized (1:1) to intrauterine device placement either within 48 hours of complete abortion (intervention) or after 2 to 4 weeks (control). Our primary outcome was self-reported use of an intrauterine device after 6 months. Secondary outcomes included expulsion rates, pain at placement, adverse events and complications, acceptability, and subsequent pregnancies and abortions. Differences in non-normal continuous variables were analyzed with the Mann-Whitney U-test and differences in dichotomous variables with the chi square or Fisher's exact tests. A P value <.05 was considered statistically significant. Group differences are presented by modified intention-to-treat and per protocol analyses.

RESULTS: Between January 2019, and June 2022, we enrolled 179 participants, of whom 90 were assigned to intervention and 89 to control. Enrolment was prematurely stopped after an interim analysis exceeded a predefined intrauterine device expulsion rate of 20%. By modified intention-to-treat, use of intrauterine device after 6 months was 50.7% (34/67) in the intervention group compared to 71.6% (48/67) in the control group (proportion difference 20.9%; 95% confidence interval 4.4%-35.9%; P=.02). The intrauterine device expulsion rate was 30.1% (22/73) in the intervention group versus 2.9% (2/70; P <.001) in the control group. Other adverse events were rare and patient acceptability was high in both groups.

CONCLUSION: Intrauterine device placement within 48 hours after second trimester medical abortion was non-superior in terms of the proportion of intrauterine device use after 6 months when compared with placement after 2 to 4 weeks. Placement within 48 hours after second trimester abortion can be used in selected individuals after counselling on expulsion risk.