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. Author manuscript; available in PMC: 2021 Aug 1.
Published in final edited form as: Thromb Res. 2020 May 11;192:40–51. doi: 10.1016/j.thromres.2020.05.008

Table 3 -.

Summary of mechanisms, benefits, and risks of different LARC options.

LARC Option Mechanism Benefits Risks
Copper IUD

  • Impairs sperm function and prevents fertilization by increasing copper ions, prostaglandins and macrophages in the uterine and tubal fluids.

  • Non-hormonal, less risk of VTE

  • Increase in painful, heavy menses after initiation.
Levonorgestrel IUD

  • Thinning the intrauterine lining, thickening the cervical mucous, and decreasing tubal motility

  • More favorable bleeding profile compared to other 2 LARCs

  • Preferred over subdermal implant due to localized effect

  • Potential slight increase in thrombotic risk compared to copper IUD
Progestin-only subdermal implant

  • thinning the intrauterine lining, thickening the cervical mucous, and decreasing tubal motility

  • suppressing ovulation

  • Convenience of application and use

  • can cause alteration in menstrual flow leading to irregular, problematic bleeding in ~20% of patients.

  • Potential increase in thrombotic risk compared to copper IUD