Hormonal contraception and bone metabolism: a systematic review.
BACKGROUND
Although a large amount of studies in the literature evaluated the effects of hormonal contraception on bone, many questions remained still unclear, such as the effect of these therapies on fracture risk.


METHODS
We performed a systematic search of the published studies from January 1975 through January 2012 on the effects of hormonal contraceptives on bone metabolism. We analyzed the overall effect on bone mineral density (BMD) and on fracture risk of combined oral contraceptives (COCs), progestogen-only contraceptives, transdermal contraceptives and vaginal ring.


RESULTS
COC therapy does not seem to exert any significant effect on BMD in the general population. In adolescents, the effects of COCs on BMD seem to be mainly determined by estrogen dose. The use of COCs in perimenopausal women seems to reduce bone demineralization and may significantly increase BMD even at a 20-mcg dose. Use of depot medroxyprogesterone acetate is associated with a decrease in BMD, although this decrease seems to be partially reversible after discontinuation. Data on other progestogen-only contraceptives, transdermal patch and vaginal ring are still limited, although it seems that these contraceptive methods do not exert any influence on BMD.


CONCLUSIONS
Hormonal contraceptives do not seem to exert any significant effect on bone in the general population. However, other randomized controlled trials are needed to evaluate the effects on fracture risk since the data available are derived from studies having the effects on BMD as the primary end point, and BMD may not accurately reflect the real fracture risk.
Department of Obstetrics and Gynecology, University of Naples Federico II, 80131 Naples, Italy. costantino.dicarlo@unina.it
Carmine
C
Nappi
Giuseppe
G
Bifulco
Giovanni A
GA
Tommaselli
Virginia
V
Gargano
Costantino
C
Di Carlo
D000818:Animals; D015519:Bone Density / Q000187:drug effects; D050071:Bone Density Conservation Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use; D001842:Bone and Bones / Q000187:drug effects* / Q000378:metabolism; D003271:Contraceptive Agents, Female / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use; D003274:Contraceptive Devices, Female; D003277:Contraceptives, Oral, Combined / Q000009:adverse effects / Q000627:therapeutic use; D003278:Contraceptives, Oral, Hormonal / Q000009:adverse effects* / Q000627:therapeutic use; D045166:Estradiol Congeners / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D005260:Female; D050723:Fractures, Bone / Q000139:chemically induced / Q000453:epidemiology* / Q000378:metabolism / Q000517:prevention & control; D006801:Humans; D058866:Osteoporotic Fractures / Q000139:chemically induced / Q000453:epidemiology / Q000378:metabolism / Q000517:prevention & control; D045167:Progesterone Congeners / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D012306:Risk; D057968:Transdermal Patch
D050071:Bone Density Conservation Agents; D003271:Contraceptive Agents, Female; D003277:Contraceptives, Oral, Combined; D003278:Contraceptives, Oral, Hormonal; D045166:Estradiol Congeners; D045167:Progesterone Congeners