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Network, Vol. 16, No. 4, Summer 1996
Oral Contraceptives
Copyright 1996, Family Health International
Oral Contraceptives Are Safe, Very Effective
However, many women use pills incorrectly or discontinue them
because of side effects or health concerns.
Oral contraceptives (OCs) are more than 99 percent effective
in preventing pregnancy when used consistently and correctly, and
they are safe for nearly all women. More than 70 million women use
the pill worldwide, but incorrect use is common, thus lowering its
annual typical effectiveness to about 92 percent.1/
OCs are among the most widely studied of all drugs. The
benefits of using them far outweigh the potential risks for almost
all women. However, oral contraceptives are not recommended for women
at high risk of cardiovascular disease or women over 35 years old who
are heavy smokers. Also, certain health problems may become worse
with pill use.
"The pill is a very safe, highly effective product," says
Dr. Laneta Dorflinger, FHI director of clinical trials. "But we need
to find ways to make sure it is used more effectively and
continuously. Since failure during typical use is quite high and
discontinuation rates are 50 percent or even higher in the first year
of use, we have to determine how to help women do better."
Side effects or health concerns are frequently mentioned as
reasons for discontinuation, she says. For example, surveys in some
countries where discontinuation rates are greater than 50 percent
show about half of the discontinuations are due to side effects or
health concerns: 24 percent of all pill users in the Dominican
Republic stopped using them within the first year for these reasons,
and 29 percent in Peru.2/ Changes in menstrual patterns are a
frequent complaint, as are headaches, nausea and, less freqently,
vomiting associated with pill use.
Allowing women to choose a contraceptive method from among
a variety of good options is one way to encourage women to continue
using any method, Dr. Dorflinger says. Counseling about potential
side effects and providing good management of medical concerns can
also improve use. For example, the quality of counseling affects how
well prepared women will be to take the pill correctly, in addition
to preparing them to handle side effects. In Zimbabwe, a survey among
OC users who had missed their daily pill found only one woman in
three who had taken the correct action after missing the pill,
illustrating one area where more thorough counseling may be able to
improve effectiveness.3/
Side effects and health
Because the hormones in the pill mimic pregnancy, the pill
has some side effects that are similar to those associated with
pregnancy. Nausea or vomiting may occur in the first few cycles of
pill use, but are less common in subsequent cycles (taking the pill
with food can minimize nausea). Women may also experience headaches,
decreased libido, and depression or mood change. Other possible side
effects include breast tenderness, acne, and dizziness.
The pill regulates a woman's menstrual cycle, decreasing the
amount of bleeding on the average by about 60 percent because of the
reduced thickness of the endometrium. This effect may be beneficial
for many women. For example, pill use can eliminate mid-cycle pain,
which some women experience, and decreases menstrual cramps. Because
of the decrease in bleeding, anemia may decrease.
A few women may experience amenorrhea, while others may have
breakthrough bleeding between periods. Breakthrough bleeding, which
can range from spotting to bleeding episodes, is generally not
harmful to a woman's health but may have some cultural or religious
significance. Typically, side effects diminish within a few months
after a woman begins OC use.
Since the pill was first introduced more than 30 years ago,
there have been hundreds of major studies on risks and benefits.
Long-term medical risks include the relationship of the pill to
cancers and to cardiovascular disease (see related article, page xx).
Most women can use the pill without safety concerns, according to
medical eligibility criteria established by the World Health
Organization (WHO).4/ It is safe for nonpregnant women past menarche
and up to 40 years old (and usually safe after age 40), with or
without children, of any weight including obese women. Postpartum
women who are not breastfeeding may begin using the pill three weeks
after giving birth, and breastfeeding women may do so after six
months, although it is better to delay pill use until breastfeeding
ends. Women can use the pill immediately postabortion. Women can use
the pill if they have mild headaches, varicose veins, anemia, a
history of diabetes during pregnancy, painful or irregular menstrual
periods, malaria, benign breast disease, or thyroid disease, or if
they carry viral hepatitis.
Some women should not use the pill under any circumstances,
according to WHO. These include women who are pregnant, have a
greatly increased risk of cardiovascular disease, are both over age
35 and smoke heavily (more than 20 cigarettes a day), and have
certain preexisting conditions that could be worsened by OCs. These
preexisting conditions include current breast cancer, benign liver
tumors, liver cancer and active viral hepatitis. High risks for
cardiovascular disease include blood pressure greater than 180/110
mm Hg, diabetes with vascular complications, complicated valvular
heart disease, and a history of any of these conditions ( deep vein
thrombosis, blood clotting in the lung, heart attack, stroke, or
severe recurrent headaches with vision problems.
Under some medical conditions, the pill is not the best
choice but is still acceptable if another method is not readily
available or acceptable, or if a provider can monitor the woman. For
example, healthy women over age 40 may generally use the pill, as can
those younger than 35 who smoke. Those with sickle cell disease can
use the pill but should be monitored due to an increased risk of
thrombosis. Those with unexplained vaginal bleeding should usually
not initiate pill use until the nature of the bleeding can be
evaluated. If taking drugs that induce liver enzymes, women should
usually not use the pill because the drugs are likely to reduce the
effectiveness of OCs. These drugs include rifampicin and
griseofulvin, which are antiboitics, and the following
anticonvulsants: phenytoin, carbamezapine, barbiturates and
primadone.
Without good counseling, a woman may not be able to
distinguish between an expected side effect and a medical problem.
A simple way to remember the danger signs of a medical problem is the
English acronym ACHES: A for "abdominal" pain that is severe; C for
severe "chest" pain, cough, shortness of breath; H for severe
"headache," dizziness, weakness or numbness; E for "eye" problems
(vision loss or blurring) or speech problems; or S for "severe" leg
pain (calf or thigh). The acronym can be modified to fit other
languages.5/ These signs help identify a possible
cardiovascular-related problem that may occur in the short term. The
long-term risk of using the pill is very small for all women in
developing countries compared to the risk of pregnancy.
There are medical benefits from pill use. Because of the
pill's excellent effectiveness in preventing pregnancy, women taking
OCs have less chance of an ectopic pregnancy, where the fertilized
egg develops outside the uterus, a life-threatening condition. Pill
use also lowers the overall risk of symptomatic pelvic inflammatory
disease (PID) by about 50 percent, because the thickened cervical
mucus helps keep bacteria out, possibly the thinner endometrium
provides less fertile ground for bacterial growth, and the decreased
menstrual flow reduces the chance of pathogenic growth or movement
of bacteria up the fallopian tubes.
False rumors about health problems can lead to
discontinuation or incorrect use. "Some women think the pill is
unnatural and may cause blocked tubes," says Dr. Olivia McDonald,
medical director of the National Family Planning Board in Jamaica,
who is working with FHI and the Medical Association of Jamaica to
provide contraceptive update seminars for Jamaican physicians, nurses
and other health professionals. "So as not to keep this unnatural
thing in their body, they don't use the pill regularly," thus
lowering effectiveness.
OCs dissolve in the stomach and are rapidly absorbed into the
bloodstream, just like other medicines. They do not build up in a
woman's body. Nor does a woman need a "rest period" from taking the
pill. Taking a rest will only increase a woman's chance of an
unplanned pregnancy. Also, pills do not cause birth defects when a
woman goes off the pill and gets pregnant.
Mechanism of Action
OCs work primarily by suppressing ovulation, while also
affecting the cervical mucus and endometrium. OCs alter the natural
production of estrogen and progestin in the body, suppressing the
follicle stimulating hormone (FSH) and luteinizing hormone (LH). When
taking the pill, the woman's brain does not trigger the normal surge
of FSH and LH needed for the follicle to mature and release an egg.
The pill keeps the cervical mucus thick to prevent sperm penetration.
It also causes the endometrium not to thicken as much as normal, thus
making implantation unlikely in the rare event that fertilization
takes place.
The cervical mucus action is particularly important for the
progestin-only pill (POP), which does not cause the extent of
ovulation suppression seen with combined pills (those containing
boeth estrogen and progestin). The mucus thickens two to three hours
after a POP is taken, but remains thick for only about 24 hours
unless another pill is taken. That is why the POP must be taken at
about the same time, every 24 hours. If a POP is missed even by just
three hours, a woman should use a back-up method if she has sexual
intercourse.
The pill used today has changed substantially from the
product that first went on the market in 1960. The original,
"high-dose" pill had up to 150 micrograms ((g) of estrogen, compared
to today's "low-dose" pill of 35 (gs or less. The amount of progestin
has also declined substantially. More recently, new progestins have
been developed for low-dose OCs, which some call the "third
generation" pills.
The new formulations were designed to reduce safety risks and
side effects. The low-dose pill, with much less estrogen, for
example, has less impact on blood pressure, blood clots, carbohydrate
metabolism and other factors for cardiovascular-related diseases.
Lower doses of estrogen have been associated with less nausea,
vomiting and headaches. Some researchers think the third generation
pills with the new progestins also reduce side effects, for example,
reducing rates of amenorrhea. Others feel the literature is not
clear.6/
Studies have not found clear connections between different
pill formulations, changes in side effects and resulting
discontinuation rates. A multicenter clinical trial involving almost
1,700 women assessed the relationship between side effects and
discontinuation rates, comparing women using a 50 (g and 35 (g pill.
The low-dose users reported significantly more intermenstrual
bleeding, while those taking high doses reported more breast
discomfort. "There were no significant differences between the groups
for gross cumulative life table discontinuation rates," reported
Vivian McLaurin and Randy Dunson of FHI, who coordinated the study.7/
The most common pill form is monophasic, where the hormone
levels are constant throughout the 21 days of active pills. Combined
OCs also exist in biphasic and triphasic forms, where the ratio of
estrogen and progestin varies among the active pills, twice during
the cycle for the biphasic and three times for the triphasic. This
variation allows the pill to mimic a woman's natural hormonal cycle
more closely in the hopes of reducing side effects, although research
has not generally shown this to be true. Most pills used in
developing countries are monophasic.
Who can take the pill?
The pill is ideally suited for women who want to delay
pregnancy and space children. Fertility almost always returns soon
after a woman quits taking the pill. The pill is a good choice for
those who want to control their own contraception. A woman can use
the pill without a partner's knowledge, if desired. Women must
arrange for resupply on a regular basis and be conscientious about
taking the pill throughout the cycle.
According to WHO, breastfeeding women who want to take the
pill should use the progestin-only pill, beginning no sooner than six
weeks after delivery if fully breastfeeding. In general, combined
oral contraceptives ae not recommended for breastfeeding mothers
because estrogen diminishes the amount of breastmilk. Although
combined OCs may be used six weeks postpartum if lactation is
well-established and other options are not available or acceptable,
ideally breastfeeding women should not use combined pills until at
least six months postpartum.
A U.S. Agency for International Development panel of experts
from several collaborating organizations, including FHI, has
identified procedures health providers need to follow in order to
distribute the pill safely.8/ The only essential procedure is good
counseling on efficacy, side effects, changes in menstrual patterns,
correct use, problems that require seeing a health-care provider, and
STD protection. Distribution does not need to be confined to clinics.
Community-based distribution systems can follow these procedures,
making the pill more easily accessible.
Sometimes unnecessary procedures are required before
prescribing the pill. Providers in many countries require that a
woman is having her menstrual period in order to get a prescription
for the pill, to ensure that she is not pregnant. This step is
medically unnecessary since screening at any time can reasonably
assure that a woman is not pregnant. An unplanned pregnancy may
result if a woman must wait several weeks before beginning the pill.
Providers can be reasonably sure that a woman is not pregnant if she
has not had pregnancy symptoms, such as absent or altered menses, and
she is within the first seven days of onset of normal menses, or has
not had recent sexual activity, or has been correctly and
consistently using a reliable method.
Some procedures, such as breast exams and blood pressure
tests, may be indicated for some women before beginning OCs. However,
pelvic exams and screening for cervical cancer and STDs should not
be routinely required for OC use, but may be appropriate for good
preventive health. Routine lab tests for cholesterol and other
functions have no relationship to safe pill use and should not be
required before pill use.
In Senegal, the expense of lab tests was compared with
possible safety risks Before 1990, full laboratory tests were
routinely given to women before they could receive the pill. A
prospective study of 410 women found that the cost to the woman of
the required laboratory tests ranged from U.S. $55 to $216, as much
as five times the monthly per capita income in Senegal. Of the 410
women, 20 were found to have possible health problems upon initial
testing. Nine of the 20 returned for retesting. Of those, only one
was confirmed as having a problem that meant she should not take the
pill. The study and a subsequent meeting led to a change in policy
in Senegal, with the government no longer requiring laboratory
testing before pills can be prescribed. "However, many doctors and
midwives have resisted the recommendation, and laboratory testing
prior to prescriptions of the pill is still widespread in urban
Senegal," reported John Stanback of FHI, the study coordinator, and
his colleagues.9/
STD/HIV considerations
Oral contraceptives do not protect against sexually
transmitted diseases (STDs), including HIV. If a woman is at risk of
becoming infected with an STD, she should use condoms consistently
regardless of her OC use.
"Pills are designed to prevent pregnancy, and they do it well," says
Dr. David Grimes, chief of obstetrics and gynecology at San Francisco
General Hospital, University of California at San Francisco, who has
published reviews on pill safety issues. "Pills are not designed to
protect against STDs. I have a coffee pot that works very well, but
it can't answer the phone. For the phone, I had to buy an answering
machine. The coffee pot was never intended to answer the phone. Nor
was the pill designed to protect against STDs."
Research is not clear on the possible relationship of OC use
to the transmission of STDs. Women using the pill are more likely to
have chlamydial cervicitis, an STD. Transmission of HIV can be more
likely if a person has an STD, including chlamydial infection.
However, research has not shown whether there is an association
between pill use and risk of HIV transmission.
A recent animal study has raised concerns about a possible
increased risk. In the study, rhesus monkeys were given doses of the
hormone progesterone, the body's natural form of progestin. The
monkeys were found to be more likely to become infected after
exposure to simian immune deficiency virus (SIV), a virus similar to
HIV in humans. However, data from human studies are inconsistent.
More research is needed to assess the implications of this study
among humans (see related article on page 18).
( William R. Finger
Footnotes
1. Moreno L, Goldman N. Contraceptive failure rates in
developing countries: Evidence from Demographic and Health Surveys.
Int Fam Plann Perspect 1991; 17(2): 44-49.
2. Dominican Republic: Demographic and Health Survey 1991.
Peru: Demographic and Health Survey 1991-1992. Calverton, MD: Macro
International Inc., 1992.
3. Zimbabwe: Demographic and Health Survey 1994. Calverton,
MD: Macro International Inc, 1995.
4. Improving Access to Quality Care in Family Planning:
Medical Eligibility Criteria for Contraceptive Use. Geneva: World
Health Organization, 1996.
5. Church CA, Rinehart W. Counseling clients about the pill.
Popul Rep 1990; Series A(8): 11.
6. Hatcher RA, Trussell J, Stewart F, et al. Contraceptive
Technology Sixteenth Revised Edition. New York: Irvington Publishers,
Inc., 1994.
7. McLaurin VL, Dunson TR. A comparative study of 35 mcg and
50 mcg combined oral contraceptives: results from a multicenter
clinical trial. Contraception 1991; 44(5): 489-503.
8. Curtis KM, Bright PL, eds. Recommendations for Updating
Selected Practices in Contraceptive Use: Results of a Technical
Meeting, Volume 1. Chapel Hill: Technical Guidance Working Group,
U.S. Agency for International Development, 1994.
9. Stanback J, Smith JB, Janowitz B, et al. Safe provision
of oral contraceptives: The effectiveness of systematic laboratory
testing in Senegal. Int Fam Plann Perspect 1994; 20(4): 147-49.
Copyright 1996, Family Health International. Any part of
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