Compared with women who didn't use OCs, however, those using a high-potency progestin
OC had an odds ratio of 0.20 for endometrial cancer while women using low-potency progestin
OCs had an odds ratio of 0.39.
* estrogen step-down ensures estrogen dominance in the first part of the cycle, thus stimulating endometrial proliferation and increasing endometrial production of progesterone receptors, which, in turn, sensitizes endometrium to the action of progestin
is also the active ingredient in the long-acting injected contraceptive Depo Provera (medroxyprogesterone) The intra-uterine device Mirena contains levonorgestrel, another progestin
, as the active ingredient.
SAN ANTONIO -- Adding a progestin
to estrogen replacement therapy markedly increases breast cancer risk over that with estrogen alone, Dr.
Oral contraceptives typically contain estrogen and progestin
. Combination pills suppress ovulation (the release of an egg) each month and therefore prevent pregnancy by denying sperm a chance to connect with an egg and fertilize it.
Newer HRT formulations--those providing continuous-combined dosing of estrogen and progestin
throughout each cycle--provide endometrial protection with lower doses of progestin
, thereby reducing the potential of progestin-related side effects.
Preliminary data suggest that progesterone may be associated with a lower risk of breast cancer than 19-nor progestins
appear to be.
No breast cancer link has been found with progestins
in birth control pills, but in a recent study, estrogen-progestin hormone replacement therapy combinations increased breast cancer relative risk in lean women by eight percent per year of use vs.
Because the addition of a progestin
to estrogen therapy in women with a uterus appears to play a key role in increasing the risk of breast cancer, and because a variety of progestins
are available (including levonorgestrel, medroxyprogesterone acetate [MPA], norethindrone acetate, and progesterone), it makes sense to ask whether some progestins
increase the risk of breast cancer more than others.
This suggests that, although the higher EE component in the 30 [micro]g pill was important when comparing 2 formulations with the same progestin
, the difference in progestins
of the two 20 [micro]g EE pills was most likely responsible for the differing rates of breakthrough bleeding.
Dr Langer will present recent updates from the Women's Health Initiative and other pivotal trials exploring the potential effects of progesterone and progestins
in menopausal hormone therapy.
at high doses suppress endometriosis disease activity.