**2. Combined hormonal contraception**

Combined hormonal contraception (CHC) is a combined formulation of progestin and synthetic estrogen [10]. This type of contraception has been utilized by women worldwide for almost 60 years, with significant changes in dosage and preparation over time [11, 12]. More than a third of women aged 16–44 years in the UK use oral contraception; in addition, oral contraceptive pills are used annually by approximately 10 million U.S. women [11]. Health care practitioners should support women to make informed decisions about choosing specific forms of CHC, ensuring that they are aware of their effectiveness—and how they compare to other contraceptive methods—as well as their potential risks and benefits.

## **2.1 Content**

CHC contains estrogen paired with a progestogen in different formulations.
