Both Estrogen and Progesterone based Oral Contraceptive use
increase stroke risk.
It
is widely accepted that oral contraceptive use increases the
risk of developing stroke. Most oral contraceptive
today are a combination of estrogen and progesterone. In the
various studies reviewed there was no uniform combination of
oral contraceptive
used in each study to draw direct comparisons thus the results
are difficult to interpret.
The
risk of developing a stroke increases with oral contraceptive
containing increasing amounts of estrogen. The manner in which
these strokes occur is poorly understood.
Progesterones
are categorized by generation, first, second, and third. Third
generation progesterones are the most recent in development and
considered to be
improvements over earlier
generations. There is evidence to suggest that women taking
oral contraceptive
containing 3rd generation progesterone are at a
2-fold greater risk of developing venous thromboembolism and
subsequent stroke than women taking oral contraceptive
containing earlier generation progesterones.
Oral
contraceptive have also be shown to cause increases in blood
pressure which could lead to strokes in women with other risk
factors that increase the chance of strokes. With the
introduction of oral contraceptives with lower
doses of estrogen the reports have been more conflicting. Some
reports found increased incidence of strokes while other reports
with lower
doses of estrogens have found no increase in strokes. Studies
of oral contraceptive with progesterone only ( which
have been advocated for women with risk factors for stroke),
have been small and conclusions should be regarded as tentative.1
