Objective: To compare 12-month pregnancy rates and time to pregnancy between women discontinuing the intrauterine device (IUD) and women discontinuing non-intrauterine contraceptive methods, including the oral contraceptive pill, contraceptive patch, vaginal ring, or etonogestrel implant.
Methods: We recruited sexually active women 18-35 years of age enrolled in the Contraceptive CHOICE Project who had discontinued a contraceptive method and desired pregnancy. We conducted surveys by telephone and collected information about reproductive histories and any pregnancies since discontinuing their contraceptive method. Participants who had not conceived at the time of enrollment were subsequently contacted for follow-up at 6 and 12 months. Pregnancy rates at 12 months were calculated. Time to pregnancy was compared using the Kaplan-Meier estimator of survival function. Cox proportional hazard models were used to adjust for confounding.
Results: We enrolled 69 former IUD users and 42 former non-IUD users. Compared to the IUD group, the non-IUD group was younger (27.6 vs. 29.5 years; p=0.01) and more likely to be nulliparous (66.7% vs. 34.8%; p=0.001). Pregnancy rates at 12-months were similar between the two groups; 81% of IUD users became pregnant compared to 70% of non-IUD users (p=0.18). In the Cox model, there was no difference in the time to pregnancy in the IUD users compared to non-IUD users (HRadj 1.19, 95% CI 0.74-1.92). African American race was associated with reduced fertility (HRadj 0.40, 95% CI 0.24-0.67).
Conclusions: We found no difference in 12-month pregnancy rates or time to pregnancy between former IUD users and users of other contraceptive methods.