Use of federal medical eligibility criteria provides evidence on contraceptive method risks and benefits

The CDC used WHO's 4 categories to describe the acceptability of prescribing a contraceptive method in relationship to specific medical conditions (Table).²

Combined hormonal contraceptives

Combined hormonal contraceptives remain relatively or absolutely contraindicated among women with hypertension, prior venous thromboembolic events, and migraines when occurring either with an aura in women of any age or migraines without aura in women aged 35 years and older (category 3/4). On the other hand, use in women with a family history of thrombosis in first-degree relatives is acceptable (category 2), as long as the patient is not known to harbor an inherited thrombophilia. Such agents are also acceptable with a history of isolated superficial thrombophlebitis and sickle cell disease (category 2).

The report also addresses contraceptive counseling in obese patients. Obese women who use combined hormonal contraceptives are more likely to experience a venous thromboembolic event than those not using such contraception, but the overall risk is small and acceptable. The advisory points out that there is only limited evidence that combined hormonal oral contraceptive effectiveness declines with rising BMI, but that the patch has been shown to be less effective when used in women weighing more than 90 kg. The report notes that in general there is no decrease in the effectiveness of combined hormonal contraceptives following restrictive-type bariatric surgery (such as banding), although procedures that result in malabsorption (ie, Roux-en-Y gastric bypass) have the potential to decrease the effectiveness of oral combined hormonal contraceptives (category 3). Since the progestin IUD is category 1 in such women and provides not only very effective contraception but also protects against-or may even lead to regression of-endometrial hyperplasia, this option should be strongly considered. Of the combined hormonal methods, the vaginal ring may be the best option.

An important series of recommendations concern women with systemic lupus erythematosus (SLE). Except for those with antiphospholipid antibodies, the benefits of combined hormonal contraceptives generally outweigh the risks among women with SLE (category 2). This also applies to women with rheumatoid arthritis. Similarly, patients with insulin-dependent diabetes who do not have vascular disease are acceptable candidates for such therapy (category 2), and estrogen and progestin are now deemed to have only a limited effect on insulin requirements. Fibroids, endometriosis, and benign causes of abnormal uterine bleeding are all category 1 conditions for combined hormonal contraceptives.

However, use of combined hormonal contraceptives (ie, pills, ring, or patch) is relatively contraindicated in women receiving traditional anticonvulsant therapy (eg, phenytoin, carbamazepine, barbiturates) because of decreased contraceptive effectiveness (category 3). When oral contraceptives are used in this setting, they should contain a minimum of 30 mcg of ethinyl estradiol. Combined hormonal contraceptives are also contraindicated in women receiving lamotrigine anticonvulsant therapy because the latter has reduced serum levels and thus reduced antiseizure efficacy in this setting (category 3). Combined hormonal contraceptives can be used freely with almost all broad-spectrum antibiotics, antifungals, and antiparasitics (category 1), although the antituberculosis agent rifampicin reduces the effectiveness of oral contraceptives (category 3).

Progestin-only contraceptives

These agents, which include the progestin-only pill, injectable depot-medroxyprogesterone acetate (Depo-Provera), progestin-releasing implants (Implanon), and a levonorgestrel-releasing intrauterine device (LNG-IUD), have broad applicability. The LNG-IUD is primarily contraindicated in the setting of pelvic infections, sexually transmitted infections, AIDS, unexplained uterine bleeding, gestational trophoblastic disease and liver tumors, as well as cervical, endometrial, and breast cancer (all categories 3 or 4). For progestin-only pills, malabsorptive bariatric surgery, traditional anticonvulsant therapy (but not lamotrigine therapy), and vascular disease are contraindications (category 3). For Depo-Provera, cerebro- and cardiovascular disease, severe hypertension (systolic blood pressure >159 mm Hg or diastolic blood pressure >99 mm Hg), liver tumors, and diabetic vascular disease are all relative contraindications (category 3). For all progestin-only contraceptives, antiphospholipid antibodies remain a relative contraindication (category 3), but not inherited thrombophilias and prior or current venous thrombotic diseases (category 2).

The CDC reported that the single most effective contraceptive method available is Implanon, which had the same low unintended pregnancy rate with both typical and perfect use of 0.05%. Implanon is a single-rod progestin implant that releases about 30 to 50 mcg per day of the third-generation progestin etonogestrel for 3 years. It represents a particularly useful and underutilized contraceptive for multiple reasons. First, as noted above, it has the highest efficacy of any method. Second, it has remarkably few contraindications (pregnancy, unexplained bleeding, breast cancer, and liver tumors). Third, insertion can be accomplished in the office with or without local anesthesia in less than 3 minutes. Fourth, complications occur in less than 1% of cases. Fifth, it is discrete and long-acting. It also dramatically reduces menstrual bleeding and can be useful in patients with menorrhagia. The mechanism for this property is the drug's dramatic reduction in endometrial blood flow.⁴ Unfortunately, this same mechanism leads to an intense angiogenic stimulus, creating large dilated superficial endometrial vessels that can cause annoying unpredictable vaginal spotting, the leading reason for discontinuation.⁵ However, on balance, it is an excellent agent.

Other contraceptive methods

The CDC investigators found no contraindications to emergency contraceptive pills (all are category 1 or 2). For copper-containing IUDs, pregnancy, puerperal sepsis, postabortal septic conditions, and pelvic tuberculosis are contraindications (categories 4/3). Barrier methods have very few contraindications except as related to AIDS; spermicides and/or diaphragms and cervical caps are contraindicated because of concerns about disruption of cervical mucosa and increased viral shedding and potential HIV transmission to unaffected sex partners. Allergies to latex are obvious contraindications to latex-containing condoms, diaphragms, and caps. Women with a history of toxic shock syndrome should avoid diaphragms, caps, and sponges.

Take-home message

The CDC report suggests that most contraceptive methods have few medical contraindications. These evidence-based guidelines provide very helpful updated guidance not only on the potential risks of various contraceptive options for women with specific medical conditions, but perhaps even more important, the safety of many specific contraceptive methods in such women. Considering that half of all US pregnancies are unplanned, this is a message that should be disseminated to our medical colleagues, our patients, and to the general public. Contraception is good preventive medicine.

REFERENCES

1. Centers for Disease Control and Prevention. US Medical Eligibility Criteria for Contraceptive Use, 2010. Adapted from the World Health Organization Medical Eligibility Criteria for Contraceptive Use, 4th edition. MMWR Early Release. May 28, 2010;59:1-86

2. World Health Organization. Medical Eligibility Criteria for Contraceptive Use. 4th ed. Geneva: World Health Organization; 2009. http://whqlibdoc.who.int/publications/2009/9789241563888_eng.pdf. Accessed June 8, 2010.

3. Curtis KM, Jamieson DJ, Peterson HB, Marchbanks PA. Adaptation of the World Health Organization's Medical Eligibility Criteria for Contraceptive Use for use in the United States. Contraception. 2010; 82(1):3-9.

4. Hickey M, Krikun G, Kodaman P, Schatz F, Carati C, Lockwood CJ. Long-term progestin-only contraceptives result in reduced endometrial blood flow and oxidative stress. J Clin Endocrinol Metab. 2006;91(9):3633-3638.

5. Lockwood CJ, Krikun G, Hickey M, Huang SJ, Schatz F. Decidualized human endometrial stromal cells mediate hemostasis, angiogenesis, and abnormal uterine bleeding. Reprod Sci. 2009;16(2):162-170.

DR LOCKWOOD is editor in chief and DR HILLARD is on the editorial advisory board.