Pregnancy outcomes with an IUD in situ: a systematic review

Background While intrauterine devices (IUDs) provide highly effective contraception, pregnancies among IUD users do rarely occur. The objective of this systematic review is to assess the evidence about risks for adverse pregnancy outcomes among women who conceive with an IUD in situ. Methods We searched MEDLINE, POPLINE, EMBASE and LILACS databases from inception through April 2011 for peer-reviewed articles containing evidence related to pregnancy outcomes among women who conceived while using copper (Cu) and levonorgestrel-releasing (LNG) IUDs. Results Nine articles met our inclusion criteria. Women with retained IUDs were at the greatest risk of adverse pregnancy outcomes, including spontaneous abortion, preterm delivery, septic abortion and chorioamnionitis. Cu-IUD removal decreased risks but not to the baseline risk of pregnancies without an IUD. One case series examined the LNG-IUD; when left in situ, 8 in 10 ended in spontaneous abortions. Conclusion Pregnancies complicated by a remaining IUD in situ were at greater risk of adverse pregnancy outcomes. Early IUD removal appeared to improve outcomes but did not entirely eliminate risks.