Contraception - Oral contraceptive pills (OCPs)

OCPs are hormonal methods of birth control. There
are two general varieties: combination oral contraceptive
pills (COCs) consist of estrogen (usually 20–50
mg ethinylestradiol) and progesterone (e.g. levonorgestrel,
norethindrone, desogestrel, norgestimate); the
progestin-only pills (POPs) contain only progesterone.
By comparison, the estrogen dose in COCs
available 30 years ago was at a dose of 50 to 80 mg
and even higher. COCs are further classified as monophasic (fixed
dose of estrogen and fixed dose of progestin), biphasic
(fixed dose of estrogen with two different progesterone
doses), or triphasic (fixed concentration of
estrogen and three increasing concentrations of progesterone).
One COC varies the dose of estrogen
throughout the cycle with a single fixed dose of progesterone.
There are no documented clinically significant
differences among these combination pills.
POPs or “mini pills” contain one of two different
kinds of progesterone. They are used by fewer than
1% of OCP users and are less effective than COCs.
Their efficacy is very sensitive to the timing of the
doses and ideally they should be taken at the same
time of day each day. A back-up contraceptive should
be instituted if the dose is delayed by more than
3 hours. Menses may be irregular or absent.
Newer COCs have been developed that offer additional
options in dosing. “Very low dose estrogen”
pills contain less than 20 mg. Although very low dose
estrogen pills minimize the risk of venous thromboembolism
compared with older estrogen doses
greater than 50 mg, they have not been proven to be
safer than OCPs with an intermediate estrogen dose
of 30 to 50 mg. They are associated with more breakthrough
bleeding, which may be problematic for
patients.
Most COCs combine 21 days of “active pill” with
7 days of placebo during which withdrawal bleeding
occurs.
More recent COCs have been introduced that
reduce or even eliminate the 7 day placebo interval.
Two 28 day products, Yaz® (3 mg of drospirenone
and 20 mcg ethinyl estradiol) and Loestein®24 FE
(1 mg norethindrone acetate and 20 mcg ethinyl
estradiol) provide active hormone for 24 instead of
21 days followed by four (not seven) inert pills.
There are also currently extended pill regimens,
which reduce the number of withdrawal bleeding
episodes per year. Seasonale® (levonorgestrel 150
mg/ethinyl estradiol 30 mg), has 84 days of active pills,
followed by 7 inert pills for a hormone-free week.
Seasonique™ (84 tablets of 150 mg levonorgestre/
estradiol 30 mg and 7 tablets containing 10 mg ethinyl
estradiol) completely eliminates the hormone free
interval by using seven days of low-dose estrogen
(10 mg ethinyl estradiol) during what otherwise would
be the pill-free interval. Breakthrough bleeding and
spotting are more common but decline with time. The
total dose of estrogen for women with these products
is greater than for the traditional 28 day pills, but the
clinical significance of this is unknown.31
OCPs using new progestins, such as norgestimate
and desogestrel, are referred to as third-generation
progestins. They are associated with fewer androgenic
side effects such as acne and hair loss, they do not
affect weight or blood pressure, and are associated
with negligible changes in blood glucose, plasma insulin
or lipids. A few years ago some studies linked them
to an increased risk of thromboembolism; however,
the evidence is inconclusive.
OCPs offer many non-contraceptive benefits.10
The newer progestin-containing OCPs increase high
density lipoprotein cholesterol (HDL-C). Perimenopausal
users of OCPs with 50 mg of estrogen demonstrate
increased bone density and may reduce their
risk of hip fracture by 44%. Triphasic OCPs combining
norgestimate are as efficacious as topical tretinoin,
benzoyl peroxide, and topical or systemic
antibiotics for the treatment of moderate acne vulgaris.
Table 7.8 lists other conditions ameliorated or
lessened by the use of oral contraceptives.
OCPs protect against certain reproductive cancers
of the endometrium and ovary. The risk of ovarian
cancer is decreased by 40% among OCP users; this
benefit persists for up to 20 years following discontinuation
of the pill. Women who use OCPs for ten or
more years reduce the risk of ovarian cancer by 80%.
BRCA-positive women experience similar reductions
in risk. The risk of endometrial cancer is decreased by 40% in women who use OCPs for at least two years,
and 60% if OCPs are used for at least four years.
The link between OCP use and breast cancer is
less conclusive. A 1996 collaborative analysis of over
53,000 women with breast cancer enrolled in 53 studies
from 25 countries concluded that “ever users” of
OCPs had a 1.07 relative risk of breast cancer unrelated
to dose or duration of use. However, OCP users
had a lower risk of metastatic disease (R ¼ 0.88
compared with non-users).32
For most women, pregnancy and/or abortion are
associated with a greater risk of mortality and morbidity
than oral contraceptives. In attempting to assist
the individual woman and her clinician in decisionmaking,
the World Health Organization has replaced
a single list of “contraindications” with four categories
of increasing “precautions” for women considering
OCPs.33 Category 1 consists of conditions for which no
restrictions to pill use are necessary. Category 2 contains
medical conditions for which the advantages
of OCPs outweigh known risks. Category 3 includes
conditions for which the clinician should exercise
caution but not necessarily refrain from prescribing.
Only category 4 conditions are felt to be so significantly
linked to OCP use that WHO recommends
patients with these conditions should refrain from
using OCPs (Table 7.9).
Thromboembolism, found in category 4, is believed
to be related less to the dose of hormone than
to the duration of use; there is a decreased risk over
time.34
Some medical conditions may worsen with the use
of OCPs. If this occurs, an oral contraceptive with a
lower estrogen dose or progestin-only oral contraceptive
can be substituted. Women with well-controlled
diabetes mellitus, hypertension, and hypertriglyceridemia
(triglycerides <750 mg/dL) should be followed
closely but most will do well on OCPs. OCPs are
generally contraindicated in women over 35 years of
age who smoke cigarettes. Newer OCPs with low doses
of estrogen or progestin-only pills are associated with
less risk of heart disease. Women who have migraines
may have risks associated with OCPs. If a woman’s
migraines are controlled, she may try a lower dose
estrogen COC or POP. If headaches worsen, OCPs
should be discontinued and another method used.
Side effects
Most women will experience breakthrough bleeding
(BTB) within the first three months of OCP use. If
pregnancy has been excluded, BTB is not necessarily
a reason to change pills. Breakthrough bleeding is
more common with POPs. It may be managed
with NSAIDs, a change to COCs, a second- or thirdgeneration
COC, or 7–13 days of oral estrogen
although there are no randomized trials which support
the efficacy of any of these regimens over another.
If the patient develops hair thinning or acne,
a product containing a low androgenic progestin such
as desogestrel or norgestimate can be considered.
Most women using OCPs will have a blood pressure
rise of less than 5 mmHg, which generally resolves
within three months of discontinuing the pill. Mood
changes and fatigue are usually related to the progestin
component. A change to a different progestin or a
decrease in dose may ameliorate symptoms.35 Some
women prefer amenorrhea to continued end-of-cycle
bleeding. This will usually be accomplished by continuing
directly with the active pills from the next
pack once a pack is completed, and neither “stopping
the pills for seven pill free days,” nor using the “placebo”
pills. Women with uncomfortable premenstrual
symptoms that occur during the pill free or placebo
days may benefit from continuing directly with the
first active pill from the next pill pack.
Missing pills
If a woman misses one pill she should take two pills
the next day and continue with the rest of the pack as
usual. If she misses two pills in the first two weeks of
the cycle, she should take two pills each day for two
days and then complete the pack as usual using a
back-up method of contraception. If she misses two
pills in the third week or misses additional pills, the
pack should be discarded and a new pack used. She
should use a back-up method of contraception for at
least seven days.36
Teratogenic effects
Teratogenic effects have probably been overstated in
the past. If a woman inadvertently becomes pregnant
while using OCPs, the pills should be discontinued
but therapeutic abortion is not necessary.
Vacations and subsequent fertility
Pill free periods are unnecessary. When she wishes
to conceive, the woman needs only to discontinue
the pill. Over 50% of women will become pregnant
in three months and 80% in one year. Folic acid
supplementation is a desirable preconception addition because OCPs may deplete folic acid stores. The
woman does not need to wait three months after
discontinuing the pill before conception.
Medications
OCPs may affect, or be affected by, the concurrent use
of other medications, especially seizure medication
and some antibiotics.
Pathophysiology
Although the primary mechanism of OCPs is to
inhibit ovulation, secondary mechanisms also occur,
especially with the low dose pills, progestin-only pills,
and inconsistent use of OCPs. These include “postfertilization”
effects. Larimore and Stanford suggest
that the evidence is compelling enough that patients
should be fully informed about the mechanisms of
action so that individuals with reservations involving
postfertilization mechanisms have the opportunity to
make a truly informed decision.37
Starting OCPs
A complete physical examination, Pap smear and
pelvic examination do not need to be performed prior
to initiating OCPs.
A quick-start method has been described, and has
the advantage of simplicity.

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