Menstrual cup and risk of IUD expulsion - a systematic review.

Background: The menstrual cup is a safe, cost-effective, and environmentally friendly menstrual product which is increasing in usage, especially in younger women. The potential risk for concomitant menstrual cup use to increase IUD expulsion has been raised over the last 10 years, however, few studies assess this. This systematic review aims to identify, appraise and synthesize the current specific evidence on menstrual cup use and risk of partial or total IUD expulsion.

Methods: PubMed, and the Cochrane Library were searched for publications available in English, until February 20th, 2021. Quantitative and qualitative studies, systematic reviews and case series reports were included. Websites of menstrual cup manufacturers LenaCup®, DivaCup®, Lunette®, AllMatters® and Saalt® were searched for warnings relevant to IUD expulsion.

Results: Seven studies were included in this review, comprising 73 partial or total IUD expulsion events in patients with IUD contraception using menstrual cups. The case study reports included two individuals who each experienced two and three expulsions respectively. Of the seven publications, three reported expulsion rates of 3.7%, 17.3% and 18.6%. Time to expulsion ranged from less than one week to two and a half years. These three studies disagree on whether there is a statistically significant association between menstrual cup use and IUD expulsion.

Conclusion: There is a possible association between menstrual cup use and increased risk of IUD expulsion and this information should be shared with patients. However evidence is scarce and high-quality randomised controlled trials are needed to address this risk and the impact of factors such as age, menstrual cup removal technique, pelvic anatomy, IUD type, and measures such as cutting the IUD strings short or delaying menstrual cup use for a period post-insertion. This research gap is limiting patients' ability to make informed choices regarding intrauterine contraception and menstrual management and must urgently be addressed in the context of rising IUD and menstrual cup use, particularly among a younger demographic who are seeking highly effective contraception.