The use of a menstrual cup as a risk factor for displacement of intrauterine devices: a case-control study.

BACKGROUND

Menstrual cups (MC) are being increasingly used for menstruation management as an alternative to tampons and sanitary pads. Intrauterine devices (IUD) are commonly and increasingly used for birth control. Displacement of an IUD from the uterine fundus can reduce its efficiency, potentially leading to unwanted pregnancies. Recently, concerns have been raised regarding a possible increase in the risk of IUD displacement, associated to the use of MC. This study measures the association between MC use and IUD displacement, taking into account the already known risk factors of IUD displacement.

METHODS AND FINDINGS

Women consulting for follow-up of an IUD in two primary care facilities in Paris were enrolled in the study between March 2020 and May 2021. IUD position was assessed by transvaginal ultrasound. Use of MC and exposition to known risk factors for IUD displacement were assessed by a standardized investigator-administered questionnaire. Frequency of MC use was compared between patients with well-positioned IUD and patients with displaced IUD. A linear regression model looked for an independent association between MC use and IUD displacement, with respect to known risk factors for IUD displacement. 747 patients were included, out of which 6.8% had a displaced IUD. MC use was reported by 17.0% of patients with a well-positioned IUD versus. 41.2% of patients with a displaced IUD. After adjustment for known risk factors of IUD displacement, MC use appeared to be significantly and independently associated with IUD displacement (aOR [95CI]: 3.09 [1.56-6.05]).

CONCLUSIONS

The use of a menstrual cup seems to be an independent risk factor for intrauterine device displacement.

CLINICAL TRIAL REGISTRATION

NCT04782583.