Here is an overview of what sex hormones are and why you should use them.
What is an IUD (In-Universe): An IUD is a long-lasting, one-way birth control pill. It's not the same as a diaphragm. An IUD works by blocking sperm from leaving the uterus, and it stops eggs from being released by the ovaries. The body doesn't release sperm normally, so a person is impotent while using an IUD. The IUD also stops ovulation, and stops the menstrual cycle. (Some women can have an IUD in place for months, and have regular periods.) In some countries, an IUD is available as a "mini-pill." An IUD works best in the first five years, but some women may be able to use it for 10 or more years. IUDs can be removed in the first year if a woman doesn't want to keep using the IUD. For the first four months after IUD insertion, it will take a woman up to six years to have her period, and the period itself can be painful. However, an IUD doesn't have to be removed for that period to occur. You don't have to worry about that until after five years of using the IUD.
When IUDs are inserted, I believe it is not necessary to use the IUD as often as people are now using it.