miércoles, 28 de septiembre de 2011

Update to CDC's U.S. Medical Eligibility Criteria for Contraceptive Use, 2010: Revised Recommendations for the Use of Contraceptive Methods During the Postpartum Period

Update to CDC's U.S. Medical Eligibility Criteria for Contraceptive Use, 2010: Revised Recommendations for the Use of Contraceptive Methods During the Postpartum PeriodWeekly
July 8, 2011 / 60(26);878-883

Initiation of contraception during the postpartum period is important to prevent unintended pregnancy and short birth intervals, which can lead to negative health outcomes for mother and infant (1). In 2010, CDC published U.S. Medical Eligibility Criteria for Contraceptive Use, 2010 (US MEC), providing evidence-based guidance for choosing a contraceptive method based on the relative safety of contraceptive methods for women with certain characteristics or medical conditions, including women who are postpartum (2). Recently, CDC assessed evidence regarding the safety of combined hormonal contraceptive use during the postpartum period. This report summarizes that assessment and the resulting updated guidance. These updated recommendations state that postpartum women should not use combined hormonal contraceptives during the first 21 days after delivery because of the high risk for venous thromboembolism (VTE) during this period. During 21--42 days postpartum, women without risk factors for VTE generally can initiate combined hormonal contraceptives, but women with risk factors for VTE (e.g., previous VTE or recent cesarean delivery) generally should not use these methods. After 42 days postpartum, no restrictions on the use of combined hormonal contraceptives based on postpartum status apply.

Importance of Contraception During the Postpartum Period

Half of all pregnancies in the United States are unintended, and these pregnancies have been associated with adverse pregnancy behaviors and outcomes, including later entry into prenatal care, decreased likelihood of smoking cessation, increased incidence of low birth weight, and decreased breastfeeding (3). In addition, short interpregnancy intervals can lead to negative consequences such as low birth weight and preterm birth (4). The postpartum period is an important time to initiate contraception because women are accessing the health-care system and might have increased motivation to avoid another pregnancy. Ovulation can occur as early as 25 days postpartum among nonbreastfeeding women, underscoring the importance of initiating contraception in the very early postpartum period (5).

However, safety of contraceptive use among postpartum women also must be considered. Hematologic changes that occur normally during pregnancy, including an increase in coagulation factors and fibrinogen and a decrease in natural anticoagulants, result in an increased risk for VTE during the postpartum period. In addition, many postpartum women have additional risk factors that further increase their risk for VTE, such as age ≥35 years, smoking, or recent cesarean delivery. This is of concern when considering postpartum contraception options because combined hormonal contraceptives (i.e., those that contain both estrogen and progestin) are themselves associated with a small increased risk for VTE among healthy women of reproductive age (6).

Rationale and Methods

US MEC, first published by CDC in 2010, was adapted from Medical Eligibility Criteria for Contraceptive Use, published by the World Health Organization (WHO) (2), which has been publishing global evidence-based contraceptive guidance since 1996. Although CDC adapted a small number of WHO recommendations and added a few new recommendations for U.S. health-care providers, the majority of the recommendations in the WHO guidance and US MEC are the same. Recommendations are provided using categories "1" to "4," based on the balance of benefits and harms signifying whether or not the contraceptive method is safe for use among women with a particular medical condition or characteristic; category 1 represents a method that is safe to use without restriction and category 4 represents an unacceptable health risk (Table 1). CDC is committed to ensuring that these recommendations remain up-to-date and based on the best available scientific evidence. An update can be triggered either by identification of new evidence or by any evidence-based updates made to the WHO global guidance.

In 2010, based on new evidence (7), WHO updated its guidance on the safety of combined hormonal contraceptives among postpartum nonbreastfeeding women to be more restrictive regarding the use of combined hormonal contraceptives during the first 42 days postpartum, particularly among women with other risk factors for VTE (6). Recommendations for breastfeeding women were not changed. Because of this WHO update, CDC initiated a process to assess whether its guidance similarly should be updated. Before this process, US MEC recommended that women less than 21 days postpartum generally should not use combined hormonal contraceptives, but that after that time, combined hormonal contraceptives could be used without restriction.

From a systematic review conducted by WHO and CDC and used in the consultation to update the WHO guidance, evidence from 13 studies showed that the risk for VTE among women within the first 42 days postpartum is 22-fold to 84-fold greater than the risk among nonpregnant, nonpostpartum reproductive age women (7). The risk is highest immediately after delivery, declining rapidly during the first 21 days, but not returning to baseline until 42 days postpartum in most studies. Use of combined hormonal contraceptives, which can cause a small increased risk for VTE in healthy reproductive age women, might theoretically pose an additional risk if used during this time. However, no evidence was identified regarding risk for VTE among postpartum women using combined hormonal contraceptives. The evidence also is limited by the small number of studies that report risk for VTE at precise intervals during the postpartum period and report baseline risk for VTE in a reference population for comparison with the risk among postpartum women. Evidence also was examined regarding the return to fertility among nonbreastfeeding postpartum women and indicated that ovulation can occur as early as 25 days postpartum, although fertile ovulation likely will not occur until at least 42 days postpartum (5).

As part of the CDC assessment, CDC recruited 13 persons from outside the agency to serve as ad hoc reviewers of the WHO revised recommendations; they were selected based on their expertise in thromboembolic disease, hematology, and family planning. The reviewers were asked to participate in a January 2011 teleconference with CDC, during which participants would review the evidence base and assess whether WHO's revised recommendations were suitable for use in the United States. A key issue identified was that immediate postpartum use of combined hormonal contraceptives would impose a high risk for VTE without any substantial benefit in pregnancy prevention because most nonlactating women will not have a fertile ovulation until at least 42 days postpartum (5). Women with risk factors for VTE in addition to being postpartum (e.g., obesity or cesarean delivery) are already at elevated risk for VTE; use of combined hormonal contraceptives theoretically would further compound that risk. Finally, access to contraceptive methods was a concern of the group; however, unlike methods that require a visit to a provider (e.g., implants and intrauterine devices [IUDs]), combined hormonal contraceptives can be started by the woman herself at the appropriate time if given a prescription or sample in advance (either before hospital discharge or at a postpartum visit).

Recommendations for Use of Combined Hormonal Contraceptives During the Postpartum Period
CDC recommends the following updated guidelines for the safety of combined hormonal contraceptives in postpartum women who are not breastfeeding (Table 1). In women who are <21 days postpartum, use of combined hormonal contraceptives represents an unacceptable health risk and should not be used (category 4). In women who are 21--42 days postpartum and have other risk factors for VTE in addition to being postpartum, the risks for combined hormonal contraceptives usually outweigh the advantages and therefore combined hormonal contraceptives generally should not be used (category 3); however, in the absence of other risk factors for VTE, the advantages of combined hormonal contraceptives generally outweigh the risks, and they can usually be used (category 2). In women who are >42 days postpartum, no restriction applies for the use of combined hormonal contraceptives because of postpartum status (category 1). Nonetheless, any other medical conditions still should be taken into consideration when determining the safety of the contraceptive method.

Separate recommendations in the 2010 US MEC for combined hormonal contraceptive use among women who are breastfeeding remain unchanged (2). These recommendations are based on evidence regarding potential negative effects of hormonal contraceptive use on breastfeeding, such as decreased duration of breastfeeding and higher rates of supplemental feeding (8). Among women who are breastfeeding and are <1 month postpartum, combined hormonal contraceptives are given a category 3 because of concerns about the effects of estrogen on breastfeeding duration and success. After 1 month, combined hormonal contraceptive use is given a category 2 for breastfeeding women. However, some of the updated recommendations based on risk for VTE in postpartum women now supersede the breastfeeding recommendations. For example, combined hormonal contraception is now classified as a category 4 (unacceptable health risk) for all postpartum women, regardless of breastfeeding status, for the first 21 days (Table 2).

Health-care providers assessing a woman's individual risk also should consider any other characteristics or medical conditions that might impact the classification. For postpartum women, this might include examining the recommendations for other risk factors for VTE, such as known thrombogenic mutations (category 4) or history of VTE with risk factors for recurrence (category 4), both of which pose an unacceptable health risk for combined hormonal contraceptive use, whether or not women are postpartum (2).

Recommendations for Use of Other Contraceptive Methods During the Postpartum Period

Recommendations for use of other contraceptives, including progestin-only hormonal contraceptives, remain unchanged and many are good options for postpartum women (Table 3). Progestin-only hormonal methods, including progestin-only pills, depot medroxyprogesterone acetate injections, and implants, are safe for postpartum women, including women who are breastfeeding, and can be initiated immediately postpartum (categories 1 and 2). IUDs, including the levonorgestrel-releasing IUD and copper-bearing IUD, also can be inserted postpartum, including immediately after delivery (categories 1 and 2) and are not associated with an increase in complications. Although IUD expulsion rates are somewhat higher when insertion occurs within 28 days of delivery, continuation rates at 6 months are similar among women who receive an IUD postpartum and those who plan for delayed insertion (9,10). Condoms can be used anytime (category 1), and the diaphragm and cap should be started at 6 weeks postpartum (category 1 after 6 weeks). In addition, women who have completed their childbearing might wish to consider sterilization at this time. Postpartum contraception is important for the health of mother and infant, and education for both health-care providers and women should focus on the range of contraception options and the safety of most of these methods during the postpartum period.

Reported by
Naomi K. Tepper, MD, Kathryn M. Curtis, PhD, Denise J. Jamieson, MD, Polly A. Marchbanks, PhD, Div of Reproductive Health, National Center for Chronic Disease Prevention and Health Promotion, CDC. Corresponding contributor: Naomi K. Tepper, ntepper@cdc.gov, 770-488-6506.

Ad hoc reviewers: David Eisenberg, MD, Washington Univ and Planned Parenthood of the St. Louis Region and Southwest Missouri, St. Louis, Missouri. Alisa Goldberg, MD, Brigham and Women's Hospital, Boston, Massachusetts. Michael Policar, MD, Univ of California, San Francisco; Emily Jackson, MD, Los Angeles, California. Andra James, MD, Duke Univ, Durham, North Carolina. Andrew Kaunitz, MD, Univ of Florida, Jacksonville, Florida. Barbara Konkle, MD, Puget Sound Blood Center, Seattle, Washington. Hal Lawrence, MD, Mary Mitchell, American College of Obstetricians and Gynecologists, Washington, DC. Charles Lockwood, MD, Yale Univ, New Haven, Connecticut. Susan Moskosky, MS, US Dept of Health and Human Svcs, Rockville, Maryland. Deborah Nucatola, MD, Planned Parenthood Federation of America, New York; Carolyn Westhoff, MD, Columbia Univ, New York, New York. Additional reviewers: Emily Godfrey, MD, Herbert Peterson, MD, Univ of North Carolina, Chapel Hill, North Carolina. Maria Steenland, MPH, National Center for Chronic Disease Prevention and Health Promotion, CDC.

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Update to CDC's U.S. Medical Eligibility Criteria for Contraceptive Use, 2010: Revised Recommendations for the Use of Contraceptive Methods During the Postpartum Period

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