Oral Contraception Increases Bone Density in Post-Menopausal Women

The results of a study published in the January 2000 issue of The Journal of Obstetrics and Gynecology showed that post-menopausal women who take oral contraception may significantly increase bone mineral density and decrease blood cholesterol levels. According to researchers at the Chulalongkorn University in Bangkok, Thailand, treating post-menopausal women with oral contraceptives is more effective than conventional hormone replacement therapy (HRT).

The study involved 80 healthy, post-menopausal women who were randomly selected to receive either a standard course of oral contraceptives or conventional HRT for one year. Though both HRT and the oral contraceptives greatly improved bone mineral density in the spine and hip, researchers saw a greater overall slowdown of bone loss in the women who were treated with oral contraceptive therapy. Oral contraceptives were also associated with greater reductions in total and LDL ("bad") cholesterol levels and diastolic blood pressure (the second number on blood pressure readings).

Sufficient bone mineral density is crucial in reducing the risk of osteoporosis, a degenerative bone disease. In women, bone loss accelerates after menopause when the ovaries stop producing estrogen, a hormone that helps maintain bone density. If this destruction/reconstruction process is unbalanced and bone loss is severe, women may experience symptoms of osteoporosis (such as back pain, height loss, curving spine, and broken or fractured bones). It is estimated that one in three women over age 50 have osteoporosis.

Though the Bangkok study needs additional confirmation, the researchers believe that oral contraceptive therapy will soon become an alternative for healthy post-menopausal women considering hormone replacement therapy (HRT). Oral contraceptives are especially beneficial for older women who have rapid bone demineralization, said Nimit Taechakraichana, MD, who led the study. Like HRT, oral contraception increases the levels of estrogen and progesterone in the body, which in turn, increase bone density and alleviate menopausal symptoms (such as hot flashes or vaginal dryness). However, oral contraception is taken for 21 days cycles followed by seven tablet-free days. Pre-menopausal women menstruate during the tablet-free intervals.

Since both HRT and oral contraception increase hormone levels, their side effects are similar. Common side effects of both therapies include:

• Nausea or vomiting
• Weight gain
• Breast swelling or tenderness
• Vaginal spot bleeding

All women should be aware of the risk factors for osteoporosis and take preventive measures to help protect against the disease. Risk factors for osteoporosis include:

• Female gender
• Advancing age (especially onset of menopause)
• Family history
• Asian or Caucasian heritage
• Small build
• History of eating disorders, diabetes, chronic diarrhea, or kidney or liver diseases

Presently, there are several other therapies available to treat women with osteoporosis These drugs include raloxifene (brand name, Evista), alendronate (brand name, Fosamax), and Calcitonin (brand name, Miacalcin).

Additional Resources and References

• The January 3, 2000 Reuters Health report, "The Pill Boosts Bone Density in Older Women," is available at http://www.reutershealth.com/eline/open/2000010305.asp
• The study referenced in this article is available to subscribers on the Journal of Obstetrics and Gynecology website at http://www.medical-library.org/j_obg.asp
• To learn more about osteoporosis, please visit http://www.imaginis.net/osteoporosis/
• To learn more about hormone replacement therapy, please visit http://www.imaginis.net/breasthealth/hrt.asp