Oral contraceptives have many benefits for control
of bleeding during the menstrual cycle. They also
have side effects and complications that make their
use unsatisfactory. Almost a third of women who discontinue
birth control pills do so because of bleeding problems.
Then what kind of bleeding can you expect when using
birth control pills? A recent supplement to the American
Journal of Obstetrics and Gynecology, 1999;180:s275-306
had several articles about oral contraceptives and
bleeding.
Does birth control pill use lessen abnormal menstrual
bleeding?
Oral contraceptives reduce the overall incidence of
bleeding problems by about 50% from what occurs in
non-contraceptive users. The rate of heavy menses
in the general population is about 2.4%. In women
on birth control pills it drops to 1.2%. Irregular
menses goes from 1.3% normally to 0.5% in oral contraceptive
users. Intermenstrual bleeding (breakthrough bleeding
as a recurrent problem) decreases from 0.5% to 0.3%
in women who have been on oral contraceptives over
time.
How much breakthrough bleeding can I expect when
starting oral contraceptives?
Studies have shown differences in breakthrough bleeding
rates in the first 3 months of women starting birth
control pills ranging from 10%-55%. Even the same
pill in different studies has widely varying rates.
The rates are so high that routine advice upon starting
the pills is to ignore the breakthrough bleeding for
the first 3 months of use; then if it persists let
the doctor know.
Does the bleeding get better the longer I take the
pills?
Yes. The intermenstrual bleeding rate drops to about
10-15% in the 4th and subsequent cycles and in most
studies does not seem to lessen after that. This is
still a high percentage of bleeding so it causes many
women to discontinue the pills.
What causes bleeding while on the birth control pills?
The most common cause of bleeding on oral contraceptives
is unknown. It is theorized to be due to atrophic
bleeding due to low estrogen. In other words, the
lining of the uterus (endometrium) is quite thin and
subject to abrasion just from normal activity.
There are three other factors known to be associated
with increasing the bleeding rate on pills: chlamydia
infection, smoking and not taking pills. In one study,
women with intermenstrual bleeding on birth control
pills had a 29% incidence of chlamydia while oral
contraceptive users without intermenstrual bleeding
had a 11% incidence of infection versus 6% in non-pill
users. Several studies have confirmed an increase
in intermenstrual bleeding associated with chlamydial
infection on pills.
Cigarette smoking has been known to be associated
with anti-estrogen effects. While new users have less
and less intermenstrual bleeding with each cycle of
pill use, non-smokers decrease breakthrough bleeding
at a much faster rate than smokers. By the 6th month
of pill use, smokers still have about twice the rate
of spotting as do non-smokers and heavy smokers (>15
cigarettes per day) have an even higher incidence
of breakthrough bleeding.
Missing pills is an obvious cause of breakthrough
bleeding. Missing one pill only slightly raises the
incidence of bleeding but by the time 3 pills are
missed, over 80% of women will have some bleeding
if not a full menses. Many women who miss pills (noncompliance)
fail to tell their doctors about that and as a result
may undergo therapies and changes in pills that are
not really needed when in fact the best therapy would
be to do nothing but take the pills more regularly.
From 25-33% of women miss more than one pill in a
cycle.
How is intermenstrual bleeding on the contraceptive
pill best treated?
The best treatment in the first 3 cycles of pill use
is just reassurance that the bleeding problems are
very likely to decrease and disappear with continued
use. If the bleeding is distressing or continues after
3 months, the best treatment is to take estrogen for
7-10 days during the first part of the cycle to build
up the endometrium and make it more resistant to sloughing.
Unfortunately most physicians do not try this treatment
first but rather switch the brand of pills in hopes
that that will decrease bleeding. There actually are
no scientific studies that test different strategies
to arrest breakthrough bleeding on the birth control
pills so we do not really know the best treatment
for this.
Do some brands of birth control pills make acne worse?
At the current time there is only one brand of birth
control pill that has FDA approval to be used to prevent
acne (Ortho Tricyclen®). Truthfully all estrogen
containing oral contraceptives decrease sebum production
which in turn usually decreases acne. Many studies
have shown up to 70% reduction in acne counts on the
face, chest, neck and back. Levonorgestrel containing
pills tend to decrease acne less than other progestins
in pills but overall there still is a reduction even
with the more androgenic progestins. The decrease
in acne is directly proportional to the decrease in
serum testosterone. The pill does this by increasing
sex hormone binding globulin which inactivates some
of the circulating testosterone.
Some women will develop or have their acne worsen
on the pill. In fact acne is is often listed as a
side effect of the pills. Studies consistently show
about 5% of women develop acne when starting pills.
What is the best regimen for taking oral contraceptives?
There are several principles that improve oral contraceptive
compliance:
Women should develop a daily routine for taking pills
so that each day, taking pills will be as regular
as brushing their teeth. Women without a daily routine
forget or miss pills 3 times more than those with
a daily routine.
Be familiar with the literature included with the
pills. Know about how the pills work and what to expect
when first starting the pills.
Know what to do if a pill is missed. Take the missed
pill or pills as soon as you remember and then continue
on to finish the pack if full menstrual bleeding has
not started. If bleeding the equivalent of menses
has started, just wait as if you finished the pills
and start a new pack of active pills after being off
5-7 days. Use back up contraception if you miss more
than one pill.
Plan a backup contraceptive method. Be prepared with
condoms and foam or indulge in abstinence until being
back on the active pills for one week.
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