How Soon After Unprotected Intercourse Can New Intrauterine Devices Be Protective?

Women often seek contraception after unprotected intercourse, but the rate of pregnancy is unknown in women who go on to obtain a levonorgestrel (52-mg) intrauterine device (LNG-IUD) up to 2 weeks afterwards. To learn more, researchers examined data from three observational studies and one randomized trial on 187 women who received an LNG-IUD 6 to 14 days after unprotected intercourse; follow-up lasted 6 months.

On the day of IUD insertion, all women had negative results on urine pregnancy tests. Participants performed urine home pregnancy tests 2 to 4 weeks after IUD insertion. Among the 187 women participating in the study, 1 became pregnant.