Risk factors for procedural interventions for retained products, after failed treatment with misoprostol or mifepristone and misoprostol for first trimester pregnancy loss - A retrospective cohort study.

OBJECTIVE

To evaluate the risk factors for procedural extraction of retained products of conception after pharmacological treatment for early pregnancy loss.

METHODS

A retrospective cohort study of patients with early pregnancy loss treated with vaginal misoprostol between November 1, 2012, and March 31, 2018, compared to patients treated with Mifepristone and misoprostol co-treatment between May 1, 2018, and February 28, 2023, who subsequently underwent a procedural intervention due to retained products of conception.

RESULTS

We identified 429 patients treated with misoprostol monotherapy and 418 treated with mifepristone-misoprostol co-treatment. Mifepristone-misoprostol co-treatment was associated with a lower averaged misoprostol dosing (1.21 vs. 1.5; P < 0.001) and a reduced rate for any procedural intervention (17.7 % vs. 23.4 %; P = 0.03). Treatment with more than one course of misoprostol was associated with an increased risk for procedural intervention (OR = 4.21 with misoprostol monotherapy, 95 % CI: 2.53-6.99, and OR = 3.75 with mifepristone-misoprostol co-treatment, 95 % CI: 2.08-6.79)

CONCLUSION

Administering mifepristone prior to misoprostol for first-trimester pregnancy loss decreases the likelihood of repeated misoprostol dosing and subsequently reduces the rate for procedural intervention for retained products of conception.