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By Robert Hatcher, MD, MPH
Professor of Gynecology and Obstetrics
Emory University School of Medicine
The Geneva-based World Health Organiza-tion (WHO) and the Washington, DC-based American College of Obstetricians and Gynecologists’ ACOG Practice Bulletin No. 18 by Andrew Kaunitz, MD,1 both respond to the important question: "What contraceptives can a woman with a history of thromboembolism use safely?"
The World Health Organization’s Medical Eligibility Criteria, initially published in 1996 and revised in 2000,2 make recommendations for women with a history of deep vein thrombosis (DVT), current DVT or pulmonary embolism (PE), women undergoing major surgery, women with a history of superficial thrombophlebitis, women with a history of or current ischemic heart disease, postpartum women at increased risk for thrombophlebitis, women following an abortion, and women with complicated or uncomplicated valvular heart disease. (For a copy of the recommendations, click here.) An explanation of the numbers used in the WHO Medical Eligibility Criteria for Starting Contraceptive Methods, referred to below as WHO-2000, appears at the end of this discussion.
The ACOG Practice Bulletin 18, referred to below as ACOG 18-2000, and the World Health Organization recommendations are in complete agreement, with the following exceptions or elaboration:
1. ACOG 18-2000 states that "Women with a documented history of unexplained VTE or VTE associated with pregnancy or exogenous estrogen use should not use combination OCs unless they are taking anticoagulants. The ACOG Practice Bulletin notes that women on warfarin for chronic anticoagulation may experience menorrhagia or hemoperitoneum following rupture of an ovarian cyst and that oral contraceptives (OCs) may actually be indicated in such women. Warfarin also is a teratogen, so effective contraception is extremely important for women anticoagulated with this medication. Use of OCs does not increase the risk of recurrent thrombosis if a woman is well-anticoagulated.
2. ACOG 18-2000 states "An OC candidate who had experienced a single episode of VTE years earlier associated with a nonrecurring risk factor (e.g., VTE occurring after immobilization following a motor vehicle accident) may not currently be at increased risk for VTE. Accordingly, the decision to initiate combination OCs in such a candidate can be individualized."
3. ACOG 18-2000 specifically points out, "Practitioners should be aware that package labeling for DMPA and for certain brands of progestin-only OCs inappropriately indicates that a history of VTE contraindicates the use of these progestin-only methods."
4. ACOG 18-2000 notes that "among women taking OCs formulated with 30 mcg of estrogen, OC induced procoagulant changes did not substantially resolve until six or more weeks after OC discontinuation." This Practice Bulletin further suggests that "the risks associated with stopping OCs one month or more before major surgery should be balanced against the risks of an unintended pregnancy." ACOG 18-2000 also suggests that heparin prophylaxis may need to be considered when a woman on combined oral contraceptives (COCs) undergoes major surgical procedures.3
ACOG 18-2000 discusses the safety of COCs in women with factor V Leiden mutation. These women are 30 times more likely than non-OC users who also are not carriers of the mutation4 to develop venous thromboembolism (VTE). ACOG 18-2000 notes that approximately 5% of U.S. OC candidates have the mutation and that "the great majority of these women will never experience VTE, even if they use combination OCs. 5 Screening to identify the 5% of U.S. OC candidates who have the mutation is neither recommended or discouraged by this ACOG Practice Bulletin. "Given the rarity of fatal VTE, one group of investigators concluded that screening of more than 1 million combination OC candidates for thrombophilic markers would, at best, prevent two OC-associated deaths."6
1. Kaunitz AM, The use of hormonal contraception in women with coexisting medical conditions. ACOG Practice Bulletin Number 18, July 2000.
2. WHO Medical Eligibility Criteria for Starting Contraceptive Methods; World Health Organization. IN PRESS; Fall 2000.
3. Bonar J. Can more be done in obstetric and gynecologic practice to reduce morbidity and mortality associated with venous thromboembolism? Am J Obstet Gynecol 1999; 180:794-791.
4. Vandenbroucke JP, Koster T, Briet E, et al. Increased risk of venous thrombosis in oral contraceptive users who are carriers of factor V Leiden mutation. Lancet 1994; 344:1,453-1,457.
5. Comp PC. Thrombophilic mechanisms of OCs. Int J Fertil Womens Med 1997; 42(suppl):170-176.
6. Price DT, Ridker PM. Factor V Leiden mutation and the risks for thromboembolic disease: A clinical perspective. Ann Inter Med 1997; 127:895-903.