This review was conducted to evaluate the evidence regarding the safety and effectiveness of intrauterine device (IUD) insertion immediately following spontaneous or induced abortion.We searched MEDLINE databases for all articles (in all languages) published in peer-reviewed journals from January 1966 through March 2010 for evidence comparing immediate postabortion IUD insertion with either no IUD insertion, insertion at a different time, insertion following first-trimester compared with second-trimester abortion or copper IUD insertion compared with hormone-releasing IUD insertion postabortion. We used standard abstraction forms to summarize and assess the quality of the evidence.The search strategy identified a total of 990 articles, of which 19 met our inclusion criteria for this review. Studies comparing immediate postabortion IUD insertion with no IUD insertion found that both groups experienced similar rates of pain and infection and a similar number of bleeding days, but one study reported that women with copper IUD insertion experienced a greater amount of bleeding than women without IUD insertion after abortion. Results from studies comparing immediate postabortion IUD insertion and insertion at a time not associated with pregnancy did not report differences between the two groups in the duration of bleeding, pain, expulsions or pelvic inflammatory disease (PID). One study however reported a greater amount of bleeding and another reported more removals for medical reasons among women with postabortion IUD insertion. Evidence from studies that examined immediate vs. delayed postabortion insertion reported minimal differences in bleeding, pain, expulsion and PID between groups. Studies comparing immediate IUD insertion after first- vs. second-trimester abortion reported no difference in removals for pain and bleeding, and an increased risk of expulsion among those women who had insertions after second-trimester abortion. In addition, women with insertions immediately after abortions occurring later in the first trimester had higher expulsion rates than those with insertions after early first-trimester abortions. Studies examining women using a copper IUD compared with a hormone-releasing IUD reported inconsistent results, with one paper reporting more bleeding days in the copper IUD group and another finding higher rates of removal for bleeding in the progesterone-releasing IUD group.Intrauterine device insertion immediately after abortion is not associated with an increased risk of adverse outcomes compared with use of other contraceptive methods or with no IUD insertion after abortion and compared with IUD insertion at times other than immediately after abortion. Intrauterine device expulsion rates, while generally low, were higher with insertions that occurred after later first-trimester abortion compared with after early first-trimester abortion and higher with IUD insertion after second-trimester abortion compared with after first-trimester abortion.