system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: I just read about a tiny hormone chip which is inserted into your arm that can prevent all periods and pregnancies for a few years. How does this work, and is it trusted? If so, how is this not a very big deal?
gpt
A small pellet or rod containing etonogestrel. It releases a constant amount for a few months to a year, and the hormone acts similar to birth control pills to prevent ovulation, and thus pregnacy.
 
The actual procedure is simple. A small incision is made and the device inserted and the skin is sealed with a stich or glue to allow the skin to heal over and seal it in. 

It can help prevent menstration by preventing the body from ovulating and shedding the uterine lining monthly lile it does normally.