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Ask the Experts: Safety and efficacy top clinicians’ queries
Are low-dose oral contraceptives (OCs) a safe form of birth control for women with well-controlled hypertension? What is the impact of weight on contraceptive efficacy? Comments are offered by the following members of the Contraceptive Technology Update Editorial Advisory Board: Andrew Kaunitz, MD, professor and assistant chair in the obstetrics and gynecology department at the University of Florida Health Science Center/ Jacksonville; Anita Nelson, MD, professor in the obstetrics and gynecology department at the University of California in Los Angeles (UCLA) and medical director of the women’s health care clinic and nurse practitioner training program at Harbor-UCLA Medical Center in Torrance; and Susan Wysocki, RNC, NP, president and chief executive officer of the Washington, DC-based National Association of Nurse Practitioners in Women’s Health.
Question: Is it within standards to start a well-controlled hypertensive client on a low-dose pill such as Alesse (Wyeth Laboratories, Philadelphia) as long as the blood pressure stays within normal range?
Kaunitz: Even contemporary (lower dose) combined oral contraceptive formulations appear to increase blood pressure. Observational data have not clarified whether use of combined OCs in women with well-controlled hypertension (and no other vascular disease risk factors such as smoking or diabetes) increases the risk of heart attack or stroke.
Here is the language included in the Washington, DC-based American College of Obstetrics and Gynecology (ACOG) Practice Bulletin: "Women with well-controlled and monitored hypertension who are aged 35 years or younger are appropriate candidates for a trial of combination OCs formulated with 35 mcg or less of estrogen, provided they are otherwise healthy, show no evidence of end-organ vascular disease, and do not smoke cigarettes. If blood pressure remains well-controlled with careful monitoring several months after initiating OCs, use can be continued."1
In healthy, nonsmoking, perimenopausal women, use of combination OCs can regularize erratic cycles, suppress vasomotor symptoms, and prevent menopausal fractures as well as ovarian and endometrial cancer. Nonetheless, clinicians should recognize that hypertension increases as women (as with men) age. Accordingly, clinicians prescribing combination OCs to perimenopausal women should closely monitor blood pressure and should be proactive regarding OC discontinuation should blood pressure rise during OC use in this setting.
Finally, clinicians should recognize that progestin-only contraceptives, such as DMPA (Depo-Provera, Pharmacia Corp., Peapack, NJ), Mirena intrauterine system (Berlex Laboratories, Montville, NJ), and minipills, as well as intrauterine devices, represent safe contraceptive choices for hypertensive women, regardless of age or other vascular disease risk factors.
Nelson: This is a very complex question. If we endorse the use of estrogen-containing hormonal contraceptives for women with well-controlled hypertension, are we assuming that a well-controlled hypertensive woman has risk factors for arterial thrombosis that are equivalent to women who are normotensive? I personally offer low-dose contraceptives to such women, but usually only if other effective methods without estrogen are not appropriate. The Geneva-based World Health Organization (WHO) does not address this issue, but it does list mild hypertension as a Category 3, meaning that the risks generally outweigh the benefits. (To access the guidelines, "Improving Access to Quality Care in Family Planning. Medical Eligibility Criteria for Contraceptive Use," on-line, go to the WHO web site, www.who.int/en/.
Clearly, if the woman has other cardiovascular risks (such as obesity, diabetes, smoking, or dyslipidemia) then the concern about giving estrogen-containing hormonal contraceptives increases significantly.
Question: My question is threefold:
Wysocki: For question one: Generally, the transdermal contraceptive would not be the first choice for a woman more than 198 pounds. However, if she is a poor pill taker, she might be better off with the patch that she will use consistently than the pill she won’t.
For question two: There are no data on weight and NuvaRing. There is one study by Holt that showed a decrease in effectiveness with lower-dose pills and women more than 150 pounds.2 However, the study has some problems in that it is retrospective and relies on patient recall of the pill they were on when they got pregnant and how much they weighed at the time. If one chooses to utilize the Holt data when counseling women who use OCs and weigh greater than 155 pounds, in terms of absolute risk, there is about a half percent increased risk of overall failure. Counseling about absolute risk may, in fact, be more realistic for our patients than the relative risk.
For question three: We can’t say whether weight applies or doesn’t apply to the pills or the ring with the limited data we have. (Scientists are further examining the weight issue, conducting a case-control study of pregnancies among current OC users. Investigators are obtaining information about women’s weight before and during OC use, and also details of their pill-taking habits and concurrent illnesses and medications that might influence OC effectiveness. CTU will report on the findings when they are published.)
1. American College of Obstetrics and Gynecology. The use of hormonal contraception in women with coexisting medical conditions. ACOG Practice Bulletin; No. 18, July 2000.
2. Holt VL, Cushing-Haugen KL, Daling JR. Body weight and risk of oral contraceptive failure. Obstet Gynecol 2002; 99:820-827.