Pregnancy outcomes following routine early provision of intrauterine device after first-trimester induced abortion-A secondary analysis of a randomized controlled trial with a 5-year follow up

Abstract

Introduction: Women undergoing an induced abortion are highly fertile and at risk of subsequent unplanned pregnancy. We recently completed a randomized clinical trial showing that routine provision of intrauterine device (IUD) at the time of abortion significantly reduced the risk of subsequent abortion during a 5-year follow up. As the use of highly effective contraception may affect all subsequent pregnancies, we analyzed the rate and distribution of all subsequent pregnancies (deliveries, miscarriages, and abortions), and the risk factors for these various pregnancy outcomes in the above-mentioned randomized clinical trial.

Material and methods: We enrolled adult women requesting first-trimester induced abortion and candidates for IUD for post-abortion contraception. Women (n = 751) were randomized to receive an IUD (either levonorgestrel-releasing IUD or copper IUD) by the clinic responsible for abortion care vs. routine care of IUD provision in primary health care with oral contraceptives for interval contraception. In the present secondary analysis, we identified all deliveries, miscarriages, and abortions in the intervention (n = 375) and control (n = 373) cohorts during the 5-year follow up using the Finnish national registries. The trial is registered at Clinical Trials (NTC01223521).

Results: The overall delivery, miscarriage, and abortion rates were 42.0, 12.0 and 32.1/1000 years of follow up (yFU). Any new pregnancy occurred in 98 women in the intervention and in 129 women in the control cohort (hazard ratio 0.73, 95% confidence interval 0.56-0.95, p = 0.023). The effect of routine IUD provision in reducing pregnancies was limited to the first 2 yFU. The number of subsequent induced abortions and of women undergoing it were significantly reduced, and time to abortion was prolonged by the intervention. However, the overall number, the number of women with subsequent delivery or miscarriage, and the times to these events were not significantly affected. History of previous pregnancy (delivery or abortion) and smoking were risk factors for subsequent induced abortion, but not for delivery or miscarriage.

Conclusions: Routine provision of IUD as part of abortion care did not reduce the rates of delivery or miscarriage during the 5-year follow up. The rates of all pregnancies and the need of subsequent induced abortion were reduced by IUD provision during the first 2 yFU.

Keywords: induced abortion; intrauterine contraception; randomized clinical trial; registry-based study.