CONTENTS

          Chapters
  1. Background
  2. Oral Contraceptive Use
  3. Benefits of Oral Contraceptives
  4. Health Risks of Oral Contraceptives
  5. Unresolved Health Issues
  6. Emergency Contraceptive Pills
  7. A Practical Guide to ECP

HIGHLIGHTS

Population Reports is published by the Population Information Program, Center for Communication Programs, The Johns Hopkins School of Public Health, 111 Market Place, Suite 310, Baltimore, Maryland 21202-4012, USA


Volume XXVIII, Number 1
Spring, 2000

Series A, Number 9
Oral Contraceptives

Other Possible Health Benefits

Use of OCs also may lower the risks of:
  • Loss of bone density,
  • Ovarian cysts,
  • Benign breast disease, and
  • Colorectal cancer
Bone density. Several studies suggest that OC use may stabilize or even increase bone density (127, 164, 247, 250, 278, 416). A retrospective study of 2,297 women, 76% of whom were postmenopausal, found that women with high bone density were significantly more likely to have used OCs than were women with low bone density. Bone mineral density increased with duration of use (247). Clinical studies suggest that the bone mass benefits of OC use are related to the estrogen dose, with estrogen doses below 15 µg resulting in a net loss of bone mass and doses greater than 25 µg resulting in a net gain (109). Therefore some very low-dose pills may not help prevent loss of bone density.

It has not been demonstrated that the effect of OCs on bone density makes a practical difference. Neither of the two major British cohort studies, the Royal College of General Practitioners study or the Oxford/FPA study, found that pill use helped to protect premenopausal women from bone fractures (87, 492).

Ovarian cysts. Several early studies indicated that high-dose OCs—those containing 50 mg or more of estrogen—protect women from functional ovarian cysts (334, 397, 493). The Oxford/FPA cohort study found that the risk of follicular ovarian cysts in current OC users was about half that in users of nonhormonal methods. The protection from corpus luteum cysts was even greater. Users of combined OCs faced about one-fifth the risk that other women faced (493). Low-dose combined and multiphasic OCs, even though they prevent ovulation effectively, may permit some follicular development and thus offer less protection against cysts (155, 436) or perhaps none at all (74, 207, 258).

Benign breast disease. Studies of women using older, higher-dose formulations found that OC use protected against fibroadenoma and fibrocystic breast disease. OC users had from one-quarter to one-half the risk of nonusers (45, 335, 398).

Protection against benign breast disease may depend on the progestin content of the pill, with more progestin offering more protection. The Oxford/FPA cohort study compared women using pills with the same amount of estrogen but with different amounts of the same progestin. Women using pills containing 2.5 or 3.0 mg of the progestin norethindrone acetate had half the incidence of fibrocystic breast disease as women who used pills with 1.0 mg norethindrone acetate. Also, protection increased with length of pill use (45). Since most OCs now in use contain lower amounts of progestin than in this study, they may offer less protection against benign breast disease (29, 265).

Colorectal cancer. Some studies have found that OC use reduces the risk of colorectal cancer (26, 135, 148, 293, 364). The largest case-control study to date found that women who had ever used OCs reduced their risk of colorectal cancer to 60% of that of nonusers and that OC use for over two years reduced risk to 50% (135). Other studies, however, have found no protective effect (252, 468, 514). Colorectal cancer is the fifth most common cancer among women worldwide (348, 542).


Previous | Next
Top of Page | Table of Contents


111 Market Place, Suite 310, Baltimore, MD 21202, USA
Phone: (410) 659.6300/Fax: (410) 659.6266/E-mail: Poprepts@jhuccp.org

Population Reports