Schedule | Lectures | Seminars | Tests | Glossary | Cases | Index | Review  | Search | Feedback


Karen Miller, M.D..
Assistant Professor
Obstetrics & Gynecology




Take Home Points


  1. To understand the theoretical vs. use effectiveness of general categories of contraceptives and contraceptives in general.

  2. To appreciate the most commonly used forms of contraception in the U.S.

  3. To understand the therapeutic problems uniquely associated with the use of oral contraceptives (OCP).

  4. To understand initiation and management of oral contraceptives.

  5. To gain some understanding of the benefits of oral contraceptives.



Theoretical effectiveness is the maximum effectiveness of that method--its effectiveness when used without error, when used perfectly, and when used exactly according to instruction.

Use effectiveness takes into account all users--those who use the method without error and those who are careless.

Breakthrough bleeding - non organic endometrial bleeding during the use of oral contraceptives. It may be due to estrogen or progestin deficiency or missing pills.

OCP - oral contraceptive pill, usually refers to combined oral contraceptive pill containing both progestin and estrogen.

Coitus interruptus is used as the primary means of contraception by at least 2% of couples in the United States. In some countries it is the most commonly used approach to birth control.

Anal intercourse is an ancient form of birth control still used in some societies.

Click here for a larger view.

Contraceptives can be divided into groups, depending on their theoretical effectiveness, their relation to the act of intercourse, and the general approach.

  1. >98%       Very effective
    95% - 98%       Moderately effective
    <95%       Poorly effective

  2. Coital independent - coital dependent - coital inhibiting - postcoital

  3. Timing - barrier methods - hormonal - inflammatory (IUD)

    There is no perfect method of contraception. Each patient must be approached individually. However, the options available to women now are vast compared to those two generations ago. Methods differ in their effectiveness, side effects, participation of the users, expense, availability, ability to be concealed, and legal/religion/FDA status. Pregnancy rates are 85 to 100 woman-years (85% per year) without contraception.

Table 1.   Failure Rates During the First Year of Use, United States
Method Percent of Women with Pregnancy
  Lowest ExpectedTypical
No method 85.0% 85.0%
Combination pill  0.13.0
Progestin only 0.5 3.0
IUDs  3.0
 Progesterone IUD2.0<2.0
 Copper T 380A 0.8 <1.0
Norplant 0.2 0.2
Female sterilization  0.2 0.4
Male sterilization  0.1 0.15
Depo-Provera 0.3 0.3
Spermicides  3.021.0
Periodic abstinence  20.0
 Ovulation method3.0 
 Post-ovulation 1.0 
Withdrawal 4.018.0
Cervical cap 6.018.0
SpongeParous women9.028.0
 Nulliparous women6.018.0
Diaphragm and spermicides 6.018.0
Condom 2.012.0



  1. OCP Contraindications

  2. Side Effects

  3. Benefits

  4. Noncontraceptive Uses of OCPs

  5. Contraceptive Steroids

  6. Progestin Administration

  7. Intrauterine Devices

  8. Charting and Fertility Awareness (Rhythm Method)

  9. Surgical Sterilization

  10. Other

  11. References



The era of modern contraception dates from 1960 when oral contraception was first approved by the US Food and Drug Administration, and intrauterine devices were re-introduced. A few catastrophes attributable to oral contraceptive pills (OCP) usage, particularly from the older higher-dose pills, caused considerable public alarm in the 1970's. Now the birth control pill has become safer and better tolerated, with reduced dosage of both the estrogen and the progestin components. The 1990's are seeing multiple reports on the health benefits of the Pill. According to the 1988 Ortho Survey, approximately 14 million women in the United States use the pill; about 60 million women worldwide use OCPs. ("OCP" usually refers to combined oral contraceptive pills containing both estrogen and progestin).

Few women are not candidates to take OCPs. Table 1 lists absolute and relative contraindications. Most of the contraindications are related to the estrogen component. Risks of hormonal contraception must always be weighed against risks of pregnancy and acceptability of other options. A woman is 15 to 20 times more likely to die from continuing a pregnancy than from using oral contraceptive pills.

  1. OCP Contraindications

    Absolute Contraindications:

    1. Thromboembolic disorder (or history thereof)
    2. Cerebrovascular accident (or history thereof)
    3. Coronary artery disease (or history thereof)
    4. Impaired liver function (current)
    5. Hepatic adenoma (or history thereof)
    6. Breast cancer, endometrial cancer, other estrogen-dependant malignancies (or history hereof)
    7. Pregnancy
    8. Undiagnosed vaginal bleeding
    9. Tobacco user over age 35

    Relative Contraindications:

    1. Migraine headaches, esp. worsening with pill use
    2. Hypertension
    3. Uterine leiomyomata
    4. Diabetes mellitus or previous gestational diabetes
    5. Elective surgery (needs 1 to 3 month discontinuation)
    6. Seizure disorder, anticonvulsant use
    7. Obstructive jaundice in pregnancy
    8. Sickle cell disease (SS or sickle C disease (SC)
    9. Gall bladder disease.

    Studies to look at the complications of oral contraceptive pills are confounded by the higher-dose pills used in the 1960's and 1970's. Estrogen and progestin doses have been steadily lowered, with attendant lowered morbidity. The currently prescribed low-dose pills (<50 micrograms of ethinyl estradiol cause cardiovascular complications; myocardial infarction, cerebrovascular accident, thromboembolism) almost exclusively in women over age 35 who smoke, or in some women with underlying medical problems, particularly with conditions predisposing to thrombosis. Healthy OCP users who undergo surgery are at increased risk of venous thrombosis and pulmonary embolism. Pills should be discontinued prior to surgery and reinstated six to eight weeks postoperatively. This, too, should be balanced against the risk of pregnancy.

  2. Side Effects

    Breakthrough bleeding is the most common side effect for which women discontinue OCP usage. This may be due to estrogen or progestin deficiency or to missing pills. Estrogen excess side effects may include nausea, water retention, vascular headaches, and chloasma. Progestin excess may lead to increased appetite and weight gain, acne, depression, and pill amenorrhea. With current low-dose formulations, most women experience mild or no side effects.

  3. Benefits

    Benefits of taking contraceptive pills have been under-publicized. Long-term use is not only safe, but it is protective against many serious disorders and nuisance complaints. There is no need for a pill-free interval for reproductive or general health.

    Noncontraceptive Benefits of OCPs

    Effective contraception
               --less need for therapeutic abortion
               --less need for surgical sterilization
    Less endometrial cancer (50% reduction)
    Less ovarian cancer (40% reduction)
    Less benign breast disease
    Fewer ovarian cysts (50% to 80% reduction)

    Fewer uterine fibroids (31% reduction)
    Fewer ectopic pregnancies
    Fewer menstrual problems
               --more regular
               --less flow
               --less dysmenorrhea
               --less anemia
    Less salpingitis (pelvic inflammatory disease)
    Less rheumatoid arthritis (60% reduction)
    Increased bone density
    Probably less endometriosis
    Possibly protection against atherosclerosis

    Besides providing protection from the above medical disorders, OCPs are used to manage many gynecologic disorders.

  4. Noncontraceptive Uses of OCPs

    Definitely beneficial:
               --Dysfunctional uterine bleeding
               --Endometriosis prophylaxis
               --Acne and hirsutism
               --Hormone replacement
               --Prevention of menstrual porphyria

    Beneficial in many cases:
               --Functional ovarian cysts
               --Premenstrual syndrome
               --Control of bleeding (dyscrasias, anovulation)

    The OCP has over 25 preparations, using two different estrogens and several different progestins. The available pills contain fixed and variable-dose ratios. All can claim >99% theoretical effectiveness. Combination pills, using both estrogen and progestin, are taken for 21 days, with a seven-day hiatus between cycles, during which time withdrawal bleeding occurs. The "mini-pill", or progestin-only pill, is taken continuously without a break; bleeding may occur irregularly, not at all, or occasionally as regular menstrual cycles. Additional information can be found under "progestins".

    The principle mechanisms of action of OCP's appear to be:

    1. Blockage of ovulation, which is mediated through hypothalamic suppression of FSH, LH and the LH surge.

    2. Creation of "hostile" (viscid) cervical mucus to hamper the transport of sperm and decrease sperm penetration.

    3. Prevention of implantation by altering the endometrium so that it is not receptive to the blastocyst.

    4. Other probable factors of decreased tubal transport and sperm capacitation.

    Choosing an oral contraceptive is simpler than it may seem. All pills protect against pregnancy in most women. Start with a preparation containing 30 or 35 mcg of ethinyl estradiol. The "newer" progestins, norgestimate and desogestrel, are reported to have equal progestin but less androgen effect than the traditional progestins (norethindrone, levonorgestrel, etc.). For new starts, ethinyl estradiol-plus-norgestimate (Ortho-Cyclen, Ortho Tri-Cyclen) may be the best option, per the theory that less androgen effect will be better for the cardiovascular system. Older low-dose oral contraceptive pills's which have been well studied and proven safe and effective, are also recommended (Norinyl 1+35, Ortho-Novum 7-7-7, Demulen 1/35, Ovcon 35, Loestrin 1.5/30, etc.). One study reported that desogestrel-containing oral contraceptive pills's (Ortho-Cept, Desogen) cause a higher incidence of thrombotic events. These data have not been corroborated, and these oral contraceptive pills's do not need to be discontinued but are not recommended for new starts. All tri-phasic pills have the same amount of estrogen throughout the month, but varying doses of progestin. This is formulated to provide less total monthly progestin exposure, theoretically enhancing cardiovascular health.

  5. Contraceptive Steroids

               Ethinyl estradiol

               Ethynodiol diacetate
               Norethindrone acetate

    (See Table 2)

    Women discontinue usage for easily definable side effects such as breakthrough bleeding, amenorrhea or nausea, or for side effects with possible relationships to pill use such as weight gain, headaches or acne. Other past users have fears regarding cancer, cardiovascular disease, and future fertility. And many women in the United States are unable to pay for contraceptives, and instead find themselves dealing with the much more expensive problem of child-rearing. Better education improves compliance. A patient should know when to contact her physician, with the potential danger signals listed below. She should also be thoroughly informed about the safety of the pill and of its benefits.

AAbdominal pain (severe)
CChest pain (severe), cough, shortness of breath
HHeadache (severe), dizziness, weakness, or numbness
EEye problems (vision loss or blurring), speech problems
SSevere leg pain (calf or thigh)
See your clinician if you have any of these problems, or if you develop depression, yellow jaundice or a breast lump.

Figure 2

    Postcoital contraception, or the "morning-after pill" consists of high doses of estrogen, progesterone, or both. A common prescription is Ovral two tablets now and two tablets in 12 hours started within 72 hours of intercourse, with failure rates from 0.16% to 1.6%. The earlier the administration, the greater the efficacy. The physician should first interview the patient as to timing of probable ovulation and intercourse and any previous unprotected intercourse. He should perform a pelvic examination and check a beta-hCG prior to administration.

    [Table 2]

  1. Progestin Administration

    Progestins can be administered on a continuous basis in oral, injectable or subdermal implant forms. In the United States, the injectable progestin is Depo-Provera, and the subdermal implant is Norplant. The main drawback to all these methods is unpredictable, irregular bleeding in many users. The advantage to injectable or implantable forms is lack of user responsibility. (Why do you suppose most contraceptive methods fail?)

    Health concerns revolve around changes in lipid levels. In general, some lowering of HDL (high-density lipo-protein, the "good" cholesterol) can be measured, but this has not been shown to contribute clinically to heart disease. Progestins do not promote clotting, therefore, they do not increase the risks of heart attack or stroke regardless of age or smoking status. Despite this, the FDA requires the same thrombosis precautions on all hormonal contraceptives because of the technical approval process.

    The oral contraceptive progestins are listed below. In the United States, the injectable progestin is Depo-Provera, and the subdermal implant is Norplant.

    Table 3.  Brand Names of Progestin-Only Pills

Progestin Dose (mg) Number of Tablets Per Package Brand Names

Norethindrone (Norethisterone) 350 42/28 Micronor, NOR-QD, Noriday, Norod
Norethindrone (Norethisterone) 75 35 Micro-Novum
Norgestrel 75 28 Ovrette, Neogest
Levonorgestrel 30 35 Microval, Noregeston, Microlut
Ethynodiol diacetate 500 28 Femulen
Lynestrenol 500 35 Exluton

    Depo-Provera is medroxyprogesterone acetate in a sustained-release suspension, 150 mg IM every three months. It is extremely effective, with failure rates from 0 to 1.2 per 100 woman-years. Studied and used extensively throughout the world, Depo-Provera is now approved by the FDA for contraception and for other indications (e.g., endometriosis, ovulation suppression).

    Norplant consists of six subdermal implants (containing 36 mg apiece) of levonorgestrel, which provide effective contraception for five years, after which the capsules should be removed. Average annual pregnancy rate is 0.6 per 100. This appears to be the most effective reversible method of long term contraception now available.

  1. Intrauterine Devices

    Intrauterine devices are plastic, polyethylene devices impregnated with barium sulfate to make them radiographic, now containing copper or progesterone, which stay in the uterine cavity. They cause a sterile spermicidal inflammatory reaction. Very few sperm reach the oviducts, and fertilization usually does not occur. If it should occur, the inflammatory reaction is also toxic to the blastocyst, and implantation is prohibited. There are two IUD's currently marketed in the United States. "ParaGard" (TCu-380A) is a copper-containing IUD with an efficacy lasting eight years. "Progestasert" is a progestin-releasing IUD which must be replaced yearly.

    First-year IUD failure rates range from < 1% to 3.7%. Pregnancy usually follows spontaneous expulsion of the IUD, occurring most commonly shortly after insertion. Cumulative four to six- year pregnancy rates are less than 1% per year. An experienced clinician has fewer failures, due mainly to correct high-fundal insertion.

    Pregnancies may occur with the IUD in place. This carries about a 55% risk of spontaneous abortion. Removal of the IUD after pregnancy is diagnosed, lowers this risk to about 25%. There may be a higher risk of septic (spontaneous) abortion, but with modern IUD's this is not certain. IUD's do not increase the risk of ectopic pregnancies, but they are more effective at preventing intrauterine than preventing ectopic pregnancies. If a woman using an IUD does become pregnant, she has a higher chance of having an ectopic pregnancy (approximately 3% to 4%).

    Concerns regarding the safety of the IUD relate mostly to pelvic inflammatory disease (PID) and subsequent infertility. Although these concerns are largely unwarranted with modern IUD's, the American public is still very suspicious of this efficacious contraceptive. The Dalkon Shield was found to be the main offender and was removed from the market. Other IUD's were removed from the market because of the cost of defending against multiple malpractice suits. The incidence of PID in monogamous IUD users is slightly greater than background risk only shortly after insertion. Exposure to more than one sexual partner greatly increases infectious risks. The ideal patient for an IUD is a monogamous woman who thinks she may be finished with childbearing.

    Click here for a larger view.

  2. Charting and Fertility Awareness (Rhythm Method)

    This is also known as "natural family planning" or periodic abstinence. These include (1) the rhythm or calendar method, (2) the basal body temperatures (BBT) method, (3) the mucus method, ovulation or Billings method, and (4) the symptothermal method. They all require couple education and motivation. It is key to remember here that ovulation occurs 14 days +/- two days before menstruation. The follicular phase of the menstrual cycle is the one that varies in length, not the luteal phase. Therefore, a woman can look back and say when she ovulated, but not as easily ahead to predict the time of the next ovulation.

    The rhythm method can only be used effectively in a woman with regular cycles. It is based on three assumptions: (1) The ovum can be fertilized for about 24 hours after ovulation. (Often states as up to 72 hours, but this would be a very rare exception.) (2) Spermatozoa retain their fertilizing ability for only about 48 hours. (3) Ovulation occurs 12 to 16 days prior to the onset of menses. After charting cycles for several months, a woman can establish her fertile period by subtracting 18 days from the length of her shortest cycle and 11 days from the longest cycle. The couple must then abstain from intercourse during this time. Another option for some couples is to use a barrier method during the fertile period. An example is as follows:

               A woman's menses start every 26 to 30 days.
               26 - 18 = 8. 30 - 11 = 19.
               The fertile interval is from day 8 to day 19 of the cycle.
               (Day #1 is always the first day of bleeding.)

    Newer developments which have improved the effectiveness and acceptability of fertility awareness family planning involve using a basal body temperature daily to determine the end of the fertile period, checking cervical mucus for clear copious, slippery status (Spinnbarkeit) to establish the onset and end of fertility, and using a combination of all of the above (symptothermal method).

    Failure rates of fertility awareness depend on the motivation and understanding of the participants. They vary from 11% to 47% and are most commonly a result of conscious deviation from the rules of the method. Most accidental (method-failure) pregnancies occur as a result of intercourse prior to ovulation.

  3. Surgical Sterilization

    Surgical sterilization is increasingly popular as a form of contraception. Approximately one million sterilizations are performed annually in the United States (recently on more women than men). The failure rate of a tubal ligation is 3 to 20 per 1000 (younger women fail more often). Failures fall into one of five categories:

    1. Luteal phase pregnancy (women who are pregnant at the time of sterilization).
    2. Surgical error (30% to 50%).
    3. Equipment failure (mainly laparoscopic methods).
    4. Fistula formation.
    5. Spontaneous reanastomosis (similar to #4).

    If a woman who has had a tubal ligation becomes pregnant, it is much more likely than normal that this will be an ectopic or tubal pregnancy, ranging from 6% to > 50% chance. However, her overall risk of an ectopic pregnancy is still lower than if she had not had the tubal ligation, since so few pregnancies occur. Procedure-related deaths are 1.5 per 100,000 compared to a maternal mortality rate of 10 per 100,000 births.

    The most common tubal ligations performed are laparoscopic cautery, Pomeroy method (especially postpartum), and the spring (Hulka) clip.

    Click here for a larger view.

    Vasectomy is the least expensive, safest, and most efficacious method of sterilization. Pregnancy rates following vasectomy are 1% to 1.5%. This is the ideal method for stable couples who are finished with child-rearing. However, since surgical procedures and anesthesia have become safer for women, they often shoulder the responsibility of limiting fertility.

  4. OTHER

    Coitus interruptus is used as the primary means of contraception by at least 2% of couples in the United States. In some countries it is the most commonly used approach to birth control. Anal intercourse is an ancient form of birth control still used in some societies. A physician should avoid being shocked by alternate sexual practices.

    Click here for a larger view.

  5. References

    1. Hatcher RA, et al. Contraceptive Technology 1990-1992, 16th revised edition. New York: Irvington Publishers, 1994.

    2. Mishell DR Jr., Davajan V, Lobo RA. Infertility, Contraception and Reproductive Endocrinology, 3rd edition. Boston: Blackwell Scientific Publications, 1991.

    3. Speroff L, Darney P. A Clinical Guide for Contraception. Baltimore: Williams & Wilkins, 1996.


Take Home Points

  1. Surgical sterilization of women and oral contraceptive use by women are the most common methods of contraception in the U.S., and are some of the most effective methods.

  2. Contraindications to combined estrogen/progestin OCP use are thromboembolic disorders, cerebrovascular accidents, coronary artery disease, liver abnormalities, estrogen dependent cancers, pregnancy, undiagnosed vaginal bleeding and tobacco use over age 35.

  3. Non contraceptive benefits of combined oral contraceptives include decreased endometrial cancer, uterine cancer, benign breast disease, ovarian cysts, uterine fibroids, ectopic pregnancy, menstrual irregularities, salpingitis, rheumatoid arthritis, endometriosis, atherosclerosis, and increased bone density.

  4. Intrauterine devices are safe and effective contraceptive methods especially for monogamous females near the end of their reproductive careers.

  5. Barrier methods and rhythm methods are highly dependent on the individuals involved.

  6. Pregnancies in women who have undergone a surgical sterilization should be considered ectopics until proven otherwise. Likewise, a positive pregnancy in a woman with an IUD may be an ectopic pregnancy.