Background: Intrauterine devices (IUDs) provide highly effective, reversible, long-term contraception that is appropriate for many women after first-trimester uterine aspiration. However, the effects of immediate versus delayed IUD insertion after uterine aspiration on rates of complications and IUD use are uncertain.
Methods: We performed a randomized noninferiority trial involving women undergoing uterine aspiration for induced or spontaneous abortion at 5 to 12 weeks of gestation who desired an IUD. Subjects were randomly assigned (in a 5:6 ratio) to IUD insertion immediately after the procedure or 2 to 6 weeks afterward (delayed insertion). The primary outcome was the rate of IUD expulsion 6 months after IUD insertion; an expulsion rate 8 percentage points higher in the immediate-insertion group was defined as inferior.
Results: Among 575 women who underwent randomization, an IUD was inserted in 100% (258 of 258) of the women in the immediate-insertion group and in 71.3% (226 of 317) of those in the delayed-insertion group (difference, 28.7 percentage points; 95% confidence interval [CI], 23.7 to 33.7). The 6-month expulsion risk was 5.0% (13 of 258 women) after immediate insertion and 2.7% (6 of 226) after delayed insertion (difference, 2.3 percentage points; 95% CI, -1.0 to 5.8), which was consistent with the predefined criterion for noninferiority. Six-month rates of IUD use were higher in the immediate-insertion group (92.3%, vs. 76.6% after delayed insertion; P<0.001). Adverse events were rare and did not differ significantly between groups. No pregnancies occurred in the immediate-insertion group; five occurred in the delayed-insertion group (P=0.07), all in women who never received an IUD.
Conclusions: The 6-month rate of expulsion of an IUD after immediate insertion was higher than but not inferior to that after delayed insertion. Immediate insertion resulted in higher rates of IUD use at 6 months, without an increased risk of complications. (Funded by the Susan Thompson Buffett Foundation; ClinicalTrials.gov number, NCT00562276.).