Why does Emsculpt make you have heavier periods for those with plastic IUD?

Any stressful event can change periods. For most, EMScuplt is not stressful per se, but might have been for your friend. It should not be done on the abdomen if you have an IUD with metal.

EMSculpt Neo has radiofrequency built into the system which helps reduce fat, both on top and behind the muscle. The older system does not treat fat.

This technology has been safely used since 2010, initially for astronauts who lost muscle mass while in space. Your treatments are only for 30 minutes and are a limited number over a month, with possible boosting with one as needed. You have much more exposure from microwaves.