Progesterone side effects
Data from:
http://courses.washington.edu/bonephys/opestrogen.html#side
What about
progesterone?
Progestins have
been given to women who still have a uterus, because estrogen
alone can increase the chance of endometrial cancer. However, in
view of the recent studies showing increased risk of breast
cancer and heart disease in women taking combination hormone
therapy, the entire set of previous recommendations must be
reconsidered.
Some studies have
shown that progestins do not result in any additional benefits
to the bone in women who are taking estrogen, either
premenopausal (Prior,
J. C.,
Hergenroeder, A. C.) or postmenopausal (Adachi,
J. D.,
PEPI writing group(1996),
Nand, S. L.). However, abstracts at the 2001 ASBMR
meetings have shown increased bone density with norethindrone
and (slightly) medroxyprogesterone acetate, when added to
estrogen.
Progestins have
several side effects, including bloating and depression. The
beneficial effects of estrogen on the serum lipids are reduced
with progestins (not as much with micronized progesterone as
with medroxyprogesterone) as shown in the PEPI study (Barrett-Connor,
E.). A study (Schairer, JAMA 2000; 283:485) of 46,355
women followed for an average of 10 years (during which time
there were 2082 cases of breast cancer) showed that the overall
risk for breast cancer was 3.9% per year in women not using
hormones, 4.5% per year in those using estrogen, and 5.8% per
year in those using both estrogen and a progestin.
Another study of
a million women from England shows
significantly more cases of breast cancer in women taking
combination estrogen and progestin than in women taking estrogen
alone. The risk per 1000 women over ten years was 5 extra cases
of breast cancer from estrogen alone and 19 extra cases with
combination.
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