Norethindrone acetate is a first-generation progestin of low progestational activity and slight estrogenic effects. The level of progestational effects refers to how successful the progestin is at preventing ovulation and lessening menstrual bleeding – the higher the better. This progestin does not prevent ovulation as well as some of the others.

This progestin tends to be less androgenic than second-generation progestins but more androgenic than third or fourth generations. The level of the androgenic effect refers to possible unwanted side effects such as acne and hirsutism (female unwanted hair growth), which are more common as the androgenic level increases. So this progestin has fewer unwanted side effects than some second-generation progestin but will have more than third and fourth generations.

Benefits

Birth control pills utilizing norethindrone acetate are less likely to cause side effects such as acne and unwanted hair growth than second-generation progestins.

The brand Estrostep may be helpful for women who experience estrogen-related side effects such as migraines, nausea or fluid retention. It works by delivering increasing levels of estrogen with a constant dose of progestin, thereby mimicking a woman’s natural menstrual cycle.

Estrostep is also one of the few birth controls prescribed to treat acne in adult women.

Risks

As a first generation progestin, norethindrone acetate has low progestational effect, which means it isn’t as good at preventing ovulation as newer generations.

Brands

Monophasic: Loestrin 1/20 Fe, Loestrin 1.5/30
Multiphasic: Estrostep Fe