Menstrual cup use linked to IUD expulsion

Among women who use IUDs as contraception, concurrent use of a menstrual cup may increase the risk of IUD expulsion, according to a study presented at ACOG 2020.

A total of 1,092 women in this prospective trial were randomized to receive one of two copper IUDs. In the first year, the women were followed up at 6 weeks, then 3, 6, and 12 months post-IUD insertion. About 24 percent of the women (n=266) used a menstrual cup during the study. Nine months after enrolment, the study protocol was amended to advise against concurrent use of a menstrual cup in women using IUDs.

Twenty-four months following enrolment, there was a higher incidence of IUD expulsion in women who used a menstrual cup compared with those who did not (17.3 percent vs 5.2 percent; odds ratio [OR], 3.81, 95 percent confidence interval [CI], 2.45–5.92). [ACOG 2020, abstract OP01-1B]

Almost one-third of the women (30.4 percent; n=14) who experienced IUD expulsion reported it occurred during removal of the menstrual cup. The rates of IUD expulsion increased from the first to second year of the study (14.3 percent vs 4.7 percent among menstrual cup users vs non-users in year 1, and 23.2 percent vs 6.5 percent in year 2; p<0.001 for both comparisons).

“Menstrual cup use for menstrual hygiene is [becoming] increasingly popular,” said the authors. “[However, we] found higher than expected IUD expulsion rates in menstrual cup users. Copper IUD users should be cautioned that concurrent menstrual cup use increases the risk of IUD expulsion and expulsion risk continues with ongoing menstrual cup use,” they said.

Previous research on the risk of IUD expulsion in menstrual cup users has been contradictory. One study assessed the IUD expulsion rate in 930 women, of whom 10.3 percent used menstrual cups, 74.2 percent tampons, and 43.2 percent sanitary pads. The study found a 2.5 percent occurrence of IUD expulsion. However, there was no difference in IUD expulsion rates between the three types of menstrual protection, suggesting that menstrual cups exert no greater effect on IUD expulsion than other forms of menstrual protection. [Contraception 2012;86:119-121]

In contrast, a study based on an internet survey of 902 women, 19.7 percent of whom were menstrual cup users, had similar findings to the present trial. Results of this study demonstrated an increased risk of IUD expulsion with concurrent menstrual cup use (OR, 2.75, 95 percent CI, 1.40–5.42; p=0.002). There was no association between concurrent sanitary pad or tampon use with IUD expulsion. [Eur J Contracept Reprod Health Care 2019;24:368-372]