Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain
the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in
Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles
and JavaScript.
The alternative text for this image may have been generated using AI.
a Images of the non-hormonal Cu-IUD (left) and hormonal IUD (right). Obtained from iStock.com/lalocraclo. Illustrations of flexible Cu-based IUDs b intrauterine ball (IUB)26, c Veracept24, and d Gynefix68.