Estrogen dominates the natural follicular phase, but its effect depends on concentration and timing. Combined birth control pills provide steady estrogen and progestin that suppress FSH, prevent the LH surge, and stop ovulation.

Oral contraceptive pills remain one of the most widely used and most effective forms of reversible contraception. They are also one of the most customizable treatment options in women's healthcare. While many patients refer to all "birth control pills" as if they are the same, there are actually important differences between formulations. These differences can affect bleeding patterns, acne, mood, bloating, cycle control, menstrual pain, and overall tolerability. At Complete