Differential effects on bone density of progestogen-only methods for contraception in premenopausal women

Bone turnover markers in women participating in a dose-finding trial of a contraceptive vaginal ring releasing Nestorone and estradiol

OBJECTIVE

To evaluate changes in the bone turnover markers CTx and P1NP during 6 months' use of novel continuous contraceptive vaginal rings delivering Nestorone (NES) 200 mcg/day and three doses of estradiol (E2) (10, 20, and 40 mcg/day).

STUDY DESIGN

This randomized trial enrolled 189 women who used two consecutive vaginal rings over 180 days. Frequent blood sampling permitted analysis of NES, E2, CTx and P1NP concentrations. The bone-turnover marker analyses included only women with complete sampling and excluded women with characteristics that might interfere with accurate measurement of bone markers such as afternoon sampling, poor ring compliance or recent pregnancy. We evaluated the change from baseline to 6 months in CTx and P1NP, stratified by ring dose and by average circulating E2 concentrations.

RESULTS

One hundred fifty-one women completed the study, and 82 women had complete data available for the bone marker analyses; the three dosage groups were balanced with regard to baseline characteristics. E2 concentrations remained low throughout treatment, regardless of which dose ring the participant used. Individual CTx changes from baseline averaged 27±56% (p<.01). Similarly, individual P1NP changes averaged 11±33% (p=.04). These increases were within the premenopausal reference ranges, and unrelated to treatment dose or to circulating E2 concentrations.

CONCLUSIONS

The low E2 dose of these rings was associated with low E2 concentrations and modest increases in serum bone turnover makers. Because we have only 6-month bone turnover markers and no direct evidence of bone loss or bone density change, these results must be interpreted with caution.

IMPLICATIONS

Nestorone, a 19-norprogesterone derivative, leads to complete ovarian suppression, which should yield excellent contraceptive effectiveness. To prevent potential adverse effects on bone, the NES contraceptive ring should be combined with higher doses of E2 than were assessed in this study.

Factors associated with bone mineral density in healthy African women

There is a paucity of normative bone mineral density (BMD) data in healthy African women. Baseline total hip and lumbar spine BMD was measured in premenopausal women. BMD distribution was comparable to that of a reference population and was impacted by several factors including contraception and duration of lactation.

INTRODUCTION

Normative data on bone mineral density (BMD) and the cumulative impact of lactation, contraceptive use, and other factors on BMD in healthy African women have not been well studied.

OBJECTIVES

The objective of this study was to determine the factors associated with BMD in healthy premenopausal women in Uganda and Zimbabwe.

METHODS

Baseline total hip (TH) and lumbar spine (LS) BMD was measured by dual x-ray absorptiometry in 518 healthy, premenopausal black women enrolling in VOICE, an HIV-1 chemoprevention trial, at sites in Uganda and Zimbabwe. Contraceptive and lactation histories, physical activity assessment, calcium intake, and serum vitamin D levels were assessed. Independent factors associated with BMD were identified using an analysis of covariance model.

RESULTS

The study enrolled 331 women from Zimbabwe and 187 women from Uganda. Median age was 29 years (IQR 25, 32) and median body mass index (BMI) was 24.8 kg/m(2) (IQR 22.2, 28.6). In univariate analyses, lower TH BMD values were associated with residence in Uganda (p < 0.001), lower BMI (p < 0.001), and any use of and duration of depot-medroxyprogresterone acetate. Use of oral contraceptives, progestin-only implants, and higher physical activity levels were protective against reduced BMD. Similarly, lower LS BMD values were associated with these same factors but also higher parity and history of breastfeeding. In a multivariable analysis, lower TH and LS BMD values were associated with enrollment in Uganda, lower BMI, and lower physical activity level; contraceptive use was associated with lower spine BMD, and breastfeeding contributed to lower total hip BMD.

CONCLUSIONS

Among healthy premenopausal women, TH and LS BMD was higher in Zimbabwe than Uganda. Additional factors independently associated with BMD included BMI, physical activity level, contraceptive use, and lactation.

Steroidal contraceptives: effect on bone fractures in women

BACKGROUND

Steroidal contraceptive use has been associated with changes in bone mineral density in women. Whether such changes increase the risk of fractures later in life is not clear. Osteoporosis is a major public health concern. Age-related decline in bone mass increases the risk of fracture, especially of the spine, hip, and wrist. Concern about bone health influences the recommendation and use of these effective contraceptives globally.

OBJECTIVES

Our aim was to evaluate the effect of using hormonal contraceptives before menopause on the risk of fracture in women.

SEARCH METHODS

Through April 2014, we searched for studies of fracture or bone health and hormonal contraceptives in MEDLINE, POPLINE, CENTRAL, EMBASE, and LILACS, as well as ClinicalTrials.gov and ICTRP. We examined reference lists of relevant articles for other trials. For the initial review, we wrote to investigators to find additional trials.

SELECTION CRITERIA

Randomized controlled trials (RCTs) were considered if they examined fractures, bone mineral density (BMD), or bone turnover markers in women with hormonal contraceptive use prior to menopause. Eligible interventions included comparisons of a hormonal contraceptive with a placebo or with another hormonal contraceptive that differed in terms of drug, dosage, or regimen. They also included providing a supplement to one group.

DATA COLLECTION AND ANALYSIS

We assessed all titles and abstracts identified through the literature searches. Mean differences were computed using the inverse variance approach. For dichotomous outcomes, the Mantel-Haenszel odds ratio (OR) was calculated. Both included the 95% confidence interval (CI) and used a fixed-effect model. Due to differing interventions, no trials could be combined for meta-analysis. We applied principles from GRADE to assess the evidence quality and address confidence in the effect estimates. In addition, a sensitivity analysis included trials that provided sufficient data for this review and evidence of at least moderate quality.

MAIN RESULTS

We found 19 RCTs that met our eligibility criteria. Eleven trials compared different combined oral contraceptives (COCs) or regimens of COCs; five examined an injectable versus another injectable, implant, or IUD; two studied implants, and one compared the transdermal patch versus the vaginal ring. No trial had fracture as an outcome. BMD was measured in 17 studies and 12 trials assessed biochemical markers of bone turnover. Depot medroxyprogesterone acetate (DMPA) was associated with decreased bone mineral density (BMD). The placebo-controlled trials showed BMD increases for DMPA plus estrogen supplement and decreases for DMPA plus placebo supplement. COCs did not appear to negatively affect BMD, and some formulations had more positive effects than others. However, no COC trial was placebo-controlled. Where studies showed differences between groups in bone turnover markers, the results were generally consistent with those for BMD. For implants, the single-rod etonogestrel group showed a greater BMD decrease versus the two-rod levonorgestrel group but results were not consistent across all implant comparisons.The sensitivity analysis included 11 trials providing evidence of moderate or high quality. Four trials involving DMPA showed some positive effects of an estrogen supplement on BMD, a negative effect of DMPA-subcutaneous on lumbar spine BMD, and a negative effect of DMPA on a bone formation marker. Of the three COC trials, one had a BMD decrease for the group with gestodene plus EE 15 μg. Another indicated less bone resorption in the group with gestodene plus EE 30 μg versus EE 20 μg.

AUTHORS' CONCLUSIONS

Whether steroidal contraceptives influence fracture risk cannot be determined from existing information. The evidence quality was considered moderate overall, largely due to the trials of DMPA, implants, and the patch versus ring. The COC evidence varied in quality but was low overall. Many trials had small numbers of participants and some had large losses. Health care providers and women should consider the costs and benefits of these effective contraceptives. For example, injectable contraceptives and implants provide effective, long-term birth control yet do not involve a daily regimen. Progestin-only contraceptives are considered appropriate for women who should avoid estrogen due to medical conditions.

Steroidal contraceptives: effect on bone fractures in women

BACKGROUND

Steroidal contraceptive use has been associated with changes in bone mineral density in women. Whether such changes increase the risk of fractures later in life is not clear. Osteoporosis is a major public health concern. Age-related decline in bone mass increases the risk of fracture, especially of the spine, hip, and wrist. Concern about bone health influences the recommendation and use of these effective contraceptives globally.

OBJECTIVES

To evaluate the effect of using hormonal contraceptives before menopause on the risk of fracture in women

SEARCH STRATEGY

We searched for studies of fracture or bone health and hormonal contraceptives in MEDLINE, POPLINE, CENTRAL, EMBASE, and LILACS, as well as ClinicalTrials.gov and ICTRP. We wrote to investigators to find additional trials.

SELECTION CRITERIA

Randomized controlled trials (RCTs) were considered if they examined fractures, bone mineral density (BMD), or bone turnover in women with hormonal contraceptive use prior to menopause. Interventions could include comparing a hormonal contraceptive with a placebo or another hormonal contraceptive or could compare providing a supplement versus a placebo.

DATA COLLECTION AND ANALYSIS

We assessed all titles and abstracts identified through the literature searches. Mean differences were computed using the inverse variance approach. For dichotomous outcomes, the Mantel-Haenszel odds ratio (OR) was calculated. Both included the 95% confidence interval (CI) and used a fixed-effect model. Due to different interventions, no trials could be combined for meta-analysis.

MAIN RESULTS

Of the 16 RCTs we found, 2 used a placebo and 1 used a non-hormonal method as the comparison, while 13 compared two hormonal contraceptives. No trial had fracture as an outcome. Most measured BMD and several assessed bone turnover. Depot medroxyprogesterone acetate (DMPA) was associated with decreased bone mineral density. The placebo-controlled trials showed BMD increases for DMPA plus estrogen supplement and decreases for DMPA plus placebo. Combination contraceptives did not appear to negatively affect bone health, but none were placebo-controlled. For implants, the single-rod etonogestrel group showed a greater BMD decrease versus the two-rod levonorgestrel group. However, results were not consistent across all implant comparisons.

AUTHORS' CONCLUSIONS

Whether steroidal contraceptives influence fracture risk cannot be determined from existing information. Many trials had small numbers of participants and some had large losses to follow up. Health care providers and women should consider the costs and benefits of these effective contraceptives. For example, injectable contraceptives and implants provide effective, long-term birth control yet do not involve a daily regimen. Progestin-only contraceptives are considered appropriate for women who should avoid estrogen due to medical conditions.

The effects of hormonal contraceptives on bone turnover markers and bone health

Sex hormones are important regulators of bone metabolism. As hormonal contraceptives contain either oestrogens or progestins, or a combination thereof, it is conceivable that these widely used agents have an effect on bone metabolism and bone health. The main users of hormonal contraceptives, adolescent girls and young women, are still building bone and accruing bone mass and may therefore be particularly susceptible to the effects of hormonal contraceptives on bone. Despite these concerns, the effects of hormonal contraceptives on bone health are still poorly understood. As biochemical markers of bone turnover have been proven useful tools in the assessment and monitoring of bone metabolism, we reviewed the effects of combined and gestagen-only hormonal contraceptives on bone turnover markers and related effects on bone mineral density and fracture risk in premenopausal women, as documented in the literature until January 2009.

Effect of depot medroxyprogesterone acetate on bone density in a Scottish industrial city

OBJECTIVE

To determine if long-term users of depot medroxyprogesterone acetate injectable contraception (DMPA) were more likely than their peers to have low bone density.

DESIGN

Cross-sectional observational study.

SETTING

The Domiciliary Family Planning Service, Glasgow, Scotland.

SUBJECTS

Clients of the Domiciliary Service who had used DMPA for contraception for longer than 5 years (mean 12 years) were invited to participate and select their own control, a friend or relative who had never used this method of contraception.

MAIN OUTCOME MEASURES

Bone density measured at the hip and lumbar spine by dual X-ray absorptiometry (DXA).

RESULTS

DMPA users had a significantly lower bone density than controls, 12-13% less at both hip and lumbar spine. This difference remained even when controlling for parity, smoking, family history of kyphosis or hip fracture, and body mass index.

CONCLUSIONS

DMPA significantly decreases bone density in a group of long-term users with significant social deprivation. The long-term significance of this remains uncertain.

Steroidal contraceptives: effect on bone fractures in women

BACKGROUND

Steroidal contraceptive use has been associated with changes in bone mineral density in women. Whether such changes increase the risk of fractures later in life is not clear. However, osteoporosis is a major public health concern. Age-related decline in bone mass increases the risk of fracture, especially of the spine, hip, and wrist. Concern about bone health influences the recommendation and use of these effective contraceptives globally.

OBJECTIVES

To evaluate the effect of using hormonal contraceptives before menopause on the risk of fracture in women

SEARCH STRATEGY

We searched for studies of fracture or bone health and hormonal contraceptives in MEDLINE, POPLINE, CENTRAL, EMBASE, and LILACS, as well as in clinical trials databases (ClinicalTrials.gov and ICTRP). We wrote to investigators to find additional trials.

SELECTION CRITERIA

Randomized controlled trials were considered if they examined fractures, bone mineral density (BMD), or bone turnover in women with hormonal contraceptive use prior to menopause. Studies were excluded if hormones were provided for treatment of a specific condition rather than for contraception. Interventions could include comparisons of a hormonal contraceptive with a placebo or with another hormonal contraceptive. Interventions could also include the provision of a supplement versus a placebo.

DATA COLLECTION AND ANALYSIS

We assessed for inclusion all titles and abstracts identified through the literature searches with no language limitation. The mean difference was computed with 95% confidence interval (CI) using a fixed-effect model.

MAIN RESULTS

We found 13 RCTs, 2 of which used a placebo. No trial had fracture as an outcome but most measured BMD. Combination contraceptives did not appear to affect bone health. Of progestin-only methods, depot medroxyprogesterone acetate (DMPA) was associated with decreased bone mineral density, while results were inconsistent for implants. The two placebo-controlled trials showed BMD increases for DMPA plus estrogen supplement and decreases for DMPA plus placebo.

AUTHORS' CONCLUSIONS

Whether steroidal contraceptives influence fracture risk cannot be determined from existing information. Due to different interventions, no trials could be combined for meta-analysis. Many trials had small numbers of participants and some had large losses to follow up. Health care providers and women should consider the costs and benefits of these effective contraceptives. For example, injectable contraceptives and implants provide effective, long-term birth control yet do not involve a daily regimen. Progestin-only contraceptives are considered appropriate for women who should avoid estrogen due to medical conditions.

Bone density recovery after depot medroxyprogesterone acetate injectable contraception use

BACKGROUND

While depot medroxyprogesterone acetate (DMPA) is a highly effective contraceptive used by millions of women, its use is associated with bone mineral density (BMD) loss, raising concerns about long-term risk of osteoporosis and/or fractures.

STUDY DESIGN

We conducted a systematic review of studies published in PubMed from 1996 to 2006, evaluating changes in BMD after discontinuation of DMPA. Ten primary clinical or observational studies were identified addressing this issue.

RESULTS

BMD consistently returned toward or to baseline values following DMPA discontinuation in women of all ages. This recovery in BMD was seen as early as 24 weeks after stopping therapy and persisted for as long as women were followed up; BMD in past DMPA users was similar to that in nonusers.

CONCLUSIONS

Bone loss occurring with DMPA use is reversible and is not likely to be an important risk factor for low bone density and fractures in older women, although data on fracture risk in DMPA users are lacking.

A three-year longitudinal evaluation of the forearm bone density of users of etonogestrel- and levonorgestrel-releasing contraceptive implants

Background

The aim of this study was to evaluate bone mineral density (BMD) at baseline and at 18 and 36 months of use of etonogestrel (ENG)-and levonorgestrel (LNG)-releasing contraceptive implants. This is a continuation of a previous study in which BMD was evaluated at baseline and at 18 months of use.

Methods

A total of 111 women, 19–43 years of age, wererandomly allocated to use one of the two implants. At 36 months of follow-up, only 36 and 39 women were still using the ENG- and LNG-releasing implants, respectively. BMD was evaluated at the distal and at the ultra-distal radius of the non-dominant forearm using dual-energy X-ray absorptiometry.

Results

There was no difference in the BMD of users of either implant at 18 and at 36 months. BMD was significantly lower at 18 and at 36 months at the distal radius in both groups of users compared to pre-insertion values; however, no difference was found at the ultra-distal radius.

Conclusion

Women 19–43 years of age using either one of these two contraceptive implants for 36 months had lower BMD values at the distal radius compared to pre-insertion values; however, no difference was found at the ultra-distal radius.

Contraceptive Implants: An Overview and Update

Contraceptive implants are safe, highly effective, and long-term methods of contraception that are widely applicable to any reproductive-aged woman. Implants require minimal user compliance and are cost-effective. The new single-rod system simplifies insertion and removal, making implants more accessible for both providers and patients. Specifically, progestin-only implants are safe options for various women including adolescents, postpartum, breast-feeding, those who are medically complicated, or those who have contraindications to or intolerance of estrogen-containing contraceptives.

Comparison of the skeletal effects of the progestogens desogestrel and levonorgestrel in oral contraceptive preparations in young women: controlled, open, partly randomized investigation over 13 cycles

AIM

This 12-month study was conducted to evaluate the skeletal effects of two monophasic oral contraceptives containing 20 mug of ethinylestradiol and 100 mug of levonorgestrel (LEVO) or 150 mug of desogestrel (DESO).

METHODS

Fifty-two women (18-24 years) were randomized into the DESO group or the LEVO group; 36 women served as controls. The areal bone mineral density (aBMD) of the femoral neck and the lumbar spine was evaluated by DXA, and parameters of bone geometry and volumetric bone mineral density (vBMD) were assessed by peripheral quantitative computed tomography at the distal radius and the tibia.

RESULTS

The LEVO group did not lose vertebral aBMD, whereas women in the DESO group lost 1.5%. At the distal radius and the tibia (shank level, 14%), LEVO induced an increase in total cross-sectional area, indicating increased periosteal bone formation. Radial trabecular vBMD declined by 1.4+/-1.8% in the DESO group, while it remained unchanged in the LEVO group.

CONCLUSION

Our study suggests that the skeletal effects of OC preparations may be influenced by progestogenic components in young women.

Hormonal contraception: recent advances and controversies

This document will outline new delivery systems and contraceptive formulations, summarize recent advances in emergency contraception, and review the effects of hormonal contraception on cancer risks, cardiovascular disease, and bone.

Steroidal contraceptives: effect on bone fractures in women

BACKGROUND

Steroidal contraceptive use has been associated with changes in bone mineral density in women. Whether such changes increase the risk of fractures later in life is not clear. However, osteoporosis is a major public health concern. Age-related decline in bone mass increases the risk of fracture, especially of the spine, hip, and wrist. Concern about bone health influences the recommendation and use of these effective contraceptives globally.

OBJECTIVES

To evaluate the effect of using hormonal contraceptives before menopause on the risk of fracture in women

SEARCH STRATEGY

We searched MEDLINE, POPLINE, CENTRAL, EMBASE, and LILACS for studies of fracture or bone health and hormonal contraceptives. We wrote to investigators to find additional trials.

SELECTION CRITERIA

Randomized controlled trials were considered if they examined fractures, bone mineral density (BMD), or bone turnover in women with hormonal contraceptive use prior to menopause. Studies were excluded if hormones were provided for treatment of a specific condition rather than for contraception. Interventions could include comparisons of a hormonal contraceptive with a placebo or with another hormonal contraceptive. Interventions could also include the provision of a supplement versus a placebo.

DATA COLLECTION AND ANALYSIS

We assessed for inclusion all titles and abstracts identified through the literature searches with no language limitation. The weighted mean difference (WMD) was computed with 95% confidence interval (CI) using a fixed-effect model.

MAIN RESULTS

No trial had fracture as an outcome. Combination contraceptives did not appear to affect bone health. Of progestin-only methods, depot medroxyprogesterone acetate (DMPA) was associated with decreased bone mineral density, while results were inconsistent for implants. The two placebo-controlled trials showed BMD increases for DMPA plus estrogen supplement and decreases for DMPA plus placebo.

AUTHORS' CONCLUSIONS

Whether steroidal contraceptives influence fracture risk cannot be determined from existing information. Due to different interventions, no trials could be combined for meta-analysis. Many trials had small numbers of participants and some had large losses to follow up. Health care providers and women should consider the costs and benefits of these effective contraceptives. For example, injectable contraceptives and implants provide effective, long-term birth control yet do not involve a daily regimen. Progestin-only contraceptives are considered appropriate for women who should avoid estrogen due to medical conditions.

Effects of the long-term use of depot medroxyprogesterone acetate as hormonal contraceptive on bone mineral density and biochemical markers of bone remodeling

PURPOSE AND METHOD

Our objective is to evaluate the effects of the long-term use of depot medroxyprogesterone acetate (DMPA) as a method of contraception on bone mineral density (BMD) and bone remodeling. Forty women (21-44 years old) who used DMPA for contraception for <1, 1-2 and >5 years, in addition to 20 age-matched healthy women (nonusers), participated in this study. Lumbar spine BMD (LS-BMD) was measured by dual-energy X-ray absorptionmetry. Serum osteocalcin (OC), a bone formation marker, was measured by enzyme amplification sorbent immunoassay. Urinary deoxypyridinoline (DPD), a bone resorption marker, was determined by enzyme immunoassay.

RESULTS

Serum OC and urinary DPD levels in women who used DMPA for <1, 1-2 and >5 years were significantly increased compared to the corresponding levels in nonusers. The increase of both biomarkers was more pronounced with longer duration of use. LS-BMD was significantly decreased in women on long-term DMPA use compared to LS-BMD in nonusers. The mean percentage decrease of LS-BMD in women who used DMPA for 1-2 and >5 years was 9% and 11.8%, respectively. LS-BMD was negatively correlated with serum OC and urinary DPD in women who used DMPA. On the other hand, LS-BMD and bone turnover were not significantly different between women who used DMPA for <1 year and nonusers.

CONCLUSION

Long-term use of DMPA (>2 years) had a significant adverse effect on BMD and induced increased bone turnover, as evidenced by a significant increase in biochemical indices of bone formation and resorption. The measurement of LS-BMD and of biomarkers of bone turnover may be recommended in women aged above 40 years and who used DMPA for a long duration (2-5 years).

Progestogen-only contraception and bone mineral density: a systematic review

Questions have been raised about the effects of progestogen-only contraceptive use on bone health, particularly among young women who have not yet reached peak bone mass and perimenopausal women who may be starting to lose bone mass. We conducted a systematic review that evaluated the association between progestogen-only contraceptive use and fracture risk or bone mineral density (BMD). We identified 39 articles from MEDLINE and EMBASE, published through July 2005. One study reported that depot medroxyprogesterone acetate (DMPA) users were more likely to experience stress fractures than nonusers; this association was not statistically significant after controlling for baseline bone density. In cross-sectional studies, the mean BMD in DMPA users was usually below that of nonusers, but within 1 SD. In longitudinal studies, BMD generally decreased more over time among DMPA users than among nonusers, but women gained BMD upon discontinuation of DMPA. Limited evidence suggested that use of progestogen-only contraceptives other than DMPA did not affect BMD.

Bone mineral density and depot medroxyprogesterone acetate

INTRODUCTION

Depot medroxyprogesterone acetate (DMPA) suppresses pituitary gonadotrophin output, thus, suppressing ovulation. Estrogen production from the ovary is also strongly inhibited, and the resulting estrogen deficiency has a detrimental impact on bone. Depot medroxyprogesterone acetate may be particularly detrimental in young women, as it may impede attainment of peak bone mass, and switching to a different contraceptive is recommended. However, the effect of sequential use of DMPA with other contraceptives in this age group has not been investigated.

METHODS

This was a cross-sectional analysis of 218 DMPA users who were 20 years or older (mean, 31 years, +/-8.9 SD) at the time of bone mineral density (BMD) estimation. The majority of women had used one or more contraceptive beside DMPA. The most commonly used alternative contraceptive was the oral combined pill (OCP). It was used by 65% of women (n=143) and for an average duration of 6 years. A logistic regression model was used to estimate the association between potential risk factors and low bone mass.

RESULTS

The prevalence of low bone mass at either hip or spine (T< or =1) was 41%. The prevalence of a T score below -2.5 was 5%, and 45% of women had already sustained one fracture. Younger age was associated with higher BMD [odds ratios (ORs), 0.054; 95% confidence interval (CI), 0.007-0.431]. However, this protective effect of age was lost once the interaction between the duration of both DMPA and OCP was introduced into the model (OR for low BMD, 1.42; 95% CI, 1.09-1.8). The use of DMPA first before ever use of OCP was particularly detrimental to BMD (OR, 3.94; 95% CI, 1.08-14.0). On the contrary, body mass index was positively associated with BMD (OR, 0.86; 95% CI, 0.8-0.9). No other demographic or anamnestic variables significantly predicted the presence of low BMD in this group of young women. This group of DMPA users appear to be at a very high risk of both low BMD and fractures, possibly independently of DMPA use. This needs to be considered when writing guidelines for risk assessment.

CONCLUSION

The use of DMPA before achievement of peak bone mass may be particularly detrimental to bone, but switching DMPA with the OCP in these women does not seem to confer specific benefit in terms of bone density. This needs to be taken into consideration when a change in contraceptive is considered purely for the sake of bone protection.

A cross-sectional study of the forearm bone density of long-term users of levonorgestrel-releasing intrauterine system

BACKGROUND

There are concerns about the effect of hormonal contraceptives on bone mineral density (BMD), but there is currently no information available on the effect of the levonorgestrel-releasing intrauterine system (LNG-IUS) on BMD. The objective of this study was to compare the BMD of LNG-IUS users with that of controls using the TCu380A intrauterine device (IUD).

MATERIALS AND METHODS

A cross-sectional study paired 53 women, aged 25-51 years, who had been using the LNG-IUS for 7 years, with 53 IUD users, according to age (+/-1 year) and body mass index (BMI; kg/m2) (+/-1). BMD was evaluated at the midshaft of the ulna and the distal radius of the nondominant forearm using double X-ray absorptiometry.

RESULTS

Mean age of women was 34 years. BMI was slightly over 25 in both groups. Estradiol was normal. Mean BMD was 0.469 +/- 0.008 and 0.467 +/- 0.009 and 0.409 +/- 0.009 and 0.411 +/- 0.009 at the midshaft of the ulna and distal radius in LNG-IUS and IUD users, respectively, without significant differences.

CONCLUSIONS

Women aged 25-51 years, using the LNG-IUS for 7 years, had a mean BMD similar to that of the control group of TCu380A IUD users.

A prospective study of the forearm bone density of users of etonorgestrel- and levonorgestrel-releasing contraceptive implants

BACKGROUND

The aim of the study was to compare bone mineral density (BMD) before insertion and at 18 months of use of etonorgestrel- and levonorgestrel-releasing contraceptive implants.

METHODS

One hundred and eleven women, 19-43 years of age, were randomly allocated to two groups: 56 to etonorgestrel and 55 to levonorgestrel. BMD was evaluated at the midshaft of the ulna and at the distal radius of the non-dominant forearm using dual-energy X-ray absorptiometry before insertion and at 18 months of use.

RESULTS

There was no difference in baseline demographic or anthropometric characteristics, or in BMD of users of either model of implant. BMD was significantly lower at 18 months of use at the midshaft of the ulna in both groups of users. However, no difference was found at the distal radius. Multiple linear regression analysis showed that the variables associated with BMD at 18 months of use in both implant groups were baseline BMD, body mass index (BMI) and difference in BMI (0 versus 18 months of use).

CONCLUSIONS

Women of 19-43 years of age using either one of the implants showed lower BMD at 18 months of use at the midshaft of the ulna, however, without a difference at the distal radius.

Effect of Norplant contraceptive on the bones of Nigerian women as assessed by quantitative ultrasound and serum markers of bone turnover

Levonorgestrel is a commonly used progestin-only contraceptive that is available as subdermal (Norplant) and intrauterine implants. Other progestin-only contraceptives such as injectable medroxyprogeterone acetate have been shown to decrease bone mineral density in long-term users. We used calcaneal ultrasound to compare the bone quality of Nigerian women between 25 and 50 years of age who had Norplant implants for 1-4 years to that of women who were not using any form of hormonal contraceptive. The mean stiffness index of women who had Norplant implants for as long as 4 years was not significantly different from that of controls. However, serum markers of bone turnover were significantly decreased in women with Norplant implants compared to age-matched controls. Serum bone-specific alkaline phosphatase was significantly decreased in subjects with Norplant implants for 1 year (13.7+/-6.0 vs. 23.0 U/L for controls, p = .001) and serum NTx was significantly decreased in subjects with implants for 3 years (10.6+/-4.9 vs. 17.6+/-7.7 bone collagen equivalents per liter for controls, p < .001). We conclude that although levonorgestrel contraceptive decreased overall bone turnover, it had no deleterious effect on the bone quality of women using Norplant implants for up to 4 years.

Impact de la contraception estroprogestative et progestative sur la densité minérale osseuse

Oral contraceptives are used by numerous women very often throughout a prolonged period of time and more and more frequently early in life, within the first reproductive years. The close relationship between oestrogen metabolism and bone turnover raises the question of the potential bone impact of oral contraceptives containing low dose of ethinyl-oestradiol and especially in adolescent girls. During adulthood, most studies have reported that oral contraceptive pills, even those containing a low dose of ethinyl-oestradiol (20 mug), had neutral, or possibly beneficial, effect on bone health. Use of oral contraceptives within the perimenopausal years also would allow to preventing bone loss, given that all vascular and metabolic contra-indications are respected. However, the skeletal effects of oral contraceptives are a greater concern for adolescent girls. Some data suggest that the use of 20 mug pills may impede the development of peak bone mass, particularly when started within the teen years. The bone impact of other hormonal contraceptive methods appears correlated with the degree of suppression of oestrogen levels. There is no effect of low dose progestagen-only pills or progestagen implants on bone health. On the other hand, administration of depot medroxyprogesterone acetate is associated with significant bone loss at all skeletal sites. However, the loss of bone mass might be reversed after discontinuation of use, especially in younger women. The bone impact of progestin only pills that have a strong antigonadotrophinic activity is not currently evaluated although there is some concern about increased bone loss in case of oestrogen deficiency period of long duration.

Effects of an Oral Contraceptive Containing Drospirenone on Bone Turnover and Bone Mineral Density

OBJECTIVE

To compare the effects of a new 21-day combined oral contraceptive containing 30 microg ethinyl/estradiol plus 3 mg drospirenone with a 21-day preparation containing 30 microg ethinyl/estradiol plus 75 microg gestodene on bone turnover and bone mineral density in young fertile women.

METHODS

A randomized, controlled trial was conducted with healthy fertile women treated with 30 microg ethinyl/estradiol plus 3 mg drospirenone (group A; n = 24), 30 microg ethinyl/estradiol plus 75 microg gestodene (group B; n = 24) and healthy controls (group C, n = 23). At 3, 6, 9, and 12 months of the study, serum and urinary calcium, osteocalcin, urinary pyridinoline, and deoxypyridinoline were measured. At baseline and after 12 months, lumbar bone mineral density was determined by dual-energy X-ray absorptiometry.

RESULTS

In groups A and B, urinary pyridinoline and deoxypyridinoline at 6, 9, and 12 months were significantly reduced in comparison with basal values and group C (P < .05). Pyridinoline and deoxypyridinoline levels were lower in group A than in group B throughout the study, but not significantly. In group A serum calcium levels were significantly increased after 6 months. At 12 months, no significant difference was detected in lumbar bone mineral density values among the 3 groups and in comparison with basal values.

CONCLUSION

Both combined oral contraceptives exert a similar positive influence on bone turnover and bone-sparing effect in young postadolescent women.

Short-term variations in bone remodeling markers of an oral contraception formulation containing 3 mg of drospirenone plus 30 μg of ethinyl estradiol: Observational study in young postadolescent women

The clinical study of treated subjects and nontreated controls was made in healthy eumenorrheic young postadolescent women volunteers in the Department of Obstetrics and Gynaecology at Cagliari University, to investigate whether an oral contraceptive (OC) containing drospirenone (3 mg) plus ethinyl estradiol (30 microg) (DRSP+EE) can affect bone metabolism. Control group (n = 26) and OC group (n = 28) women did not differ in age, body mass index, waist-to-hip ratio and main outcome measures [urinary levels of deoxypyridinoline and pyridinoline, serum levels of osteocalcin, bone specific alkaline phosphatase (bSAP), total testosterone (total-T), sex hormone-binding globulin (SHBG), progesterone and bone mineral density (BMD) at the heel]. The control group was studied at the luteal phase (LP) during both the first and the sixth menstrual cycle; the OC group was studied during the first cycle at the LP, and on days 16-18 of the sixth cycle of DRSP+EE treatment. At the sixth cycle, in the control group, the main outcome measures did not change compared to baseline. In the OC group, deoxypyridinoline, pyridinoline, osteocalcin, bSAP, total-T and progesterone levels were reduced, whereas SHBG levels were increased. The BMD was unchanged compared to baseline. The results suggest that 6-month DRSP+EE treatment decreases bone turnover.

Hormonal contraception: recent advances and controversies

This document will outline new delivery systems and contraceptive formulations, summarize recent advances in emergency contraception, and review the effects of hormonal contraception on cancer risks, cardiovascular disease, and bone.

Hormonal contraception: Recent advances and controversies

This document will outline new delivery systems and contraceptive formulations, summarize recent advances in emergency contraception, and review the effects of hormonal contraception on cancer risks, cardiovascular disease, and bone.

Bone Mineral Density in Adolescent Women Using Depot Medroxyprogesterone Acetate

PURPOSE

To present current data on bone mineral density (BMD) in adolescent women using the long-acting contraceptive depot medroxyprogesterone acetate (DMPA) and also to discuss the importance of developing maximal bone mass during adolescence to offset bone demineralization later in life.

DATA SOURCES

Research-based articles in the medical literature, review articles, and recommendations from the American Academy of Pediatrics and the National Osteoporosis Foundation.

CONCLUSIONS

Osteoporosis is a preventable disease that affects millions of Americans, particularly older women. Factors influencing the attainment and maintenance of peak bone mass during childhood and adolescence affect the future risk of fractures. Although longitudinal studies conducted on adolescent women using DMPA are very limited, findings suggest that adolescents are losing bone density during a time of expected bone accretion.

IMPLICATIONS FOR PRACTICE

Clinicians must consider all the risks and benefits when prescribing contraceptives to adolescents. By themselves, the findings related to BMD and DMPA use by adolescents are not sufficient to limit the use of DMPA as a contraceptive method. However, clinicians must take into account the addition of other modifying factors associated with BMD that may contribute to overall bone loss in adolescent females. More prospective data on the long-term use of DMPA by adolescents are needed to determine DMPA's effect on bone loss and to determine if bone loss is transient in adolescents.

Risks and benefits, advantages and disadvantages of levonorgestrel-releasing contraceptive implants

Levonorgestrel-releasing implants are long acting contraceptives, approved for 5 years of continuous use. Two marketed systems, the six capsule Norplant use of tradenames is for product identification purposes only and does not imply endorsement. and the two rod Jadelle, have essentially equal rates of drug release, pregnancy and adverse events over 5 years of use. Randomised clinical trials and controlled cohort observations indicate that for the first 3 years, when pregnancy rates are at or almost zero, no other contraceptive system is more effective, although etonogestrel implants provide equal effectiveness. Annual pregnancy rates rise in the fifth year of continuous use but remain below 1 per 100 women. Annual pregnancy rates of Norplant users remain below 1 per 100 throughout 7 years of continuous use. Levonorgestrel implants provide low progestogen doses; 40-50 microg/day at 1 year of use, decreasing to 25-30 microg/day in the fifth year. Serum levels of levonorgestrel at 5 years are 60-65% of those levels measured at 1 month of use. Adverse effects with levonorgestrel implants are similar to those observed with progestogen only and combined oral contraceptives. Risks of ectopic pregnancy, other pregnancy complications and pelvic inflammatory disease are reduced in comparison with those of women using copper or non-medicated intrauterine devices. Risks of developing gallbladder disease and hypertension or borderline hypertension, although small, are about 1.5 and 1.8 times greater, respectively, in women using levonorgestrel implants than in women not using hormonal contraception. Other serious diseases have not been found to occur significantly more frequently in levonorgestrel implant users than in women not using hormonal contraception. The great majority of levonorgestrel implant users experience menstrual problems, but serious bleeding problems are not more frequent than in controls. Other health problems reported more frequently by levonogestrel implant users than by women not using hormonal contraception in a study of 16000 women included skin conditions, headache, upper limb neuropathies, dizziness, nervousness, malaise, minor visual disturbances, respiratory conditions, arthropathies, weight change, anxiety and non-clinical depression. Clinical depression is not more frequent in women using implants compared with those not using hormonal contraception (i.e. using intrauterine devices, sterilisation). Removal problems occur less frequently with Jadelle than with Norplant. The mean removal time for Jadelle is half that of Norplant. Levonorgestrel implants in nationally representative scientific samples, in randomised trials, and in controlled cohort studies have continuation rates as high as or higher than any other reversible contraceptive over a duration of 5 years. This would imply that the satisfaction women derive from the contraceptive effectiveness of levonorgestrel implants greatly outweighs the dissatisfaction that may accompany menstrual disturbances and other adverse effects associated with implants.

Controversies in adolescent hormonal contraception

Unintended pregnancy and abortion rates among US adolescents remain high although hormonal contraception is safe and effective in this population. Controversies affecting the provision of hormonal contraception for adolescents include the side effects of oral contraceptives, the possibility that progestin-only injectables lead to decreased bone health, and debate as to whether emergency contraception should be available to teens without a prescription. Each of these issues is addressed with a review of relevant literature.

Risk-benefit effects of implantable contraceptives in women

Contraceptive implant technology has been used by millions of women throughout the world. The three marketed implant systems today are levonorgestrel-releasing implants: Norplant and Jadelle, and a single etonogestrel-releasing implant, Implanon. The main benefits common to these delivery systems are their safety, high effectiveness, ease of use, long duration of action (3 - 5 years) and reversibility. Bleeding disturbances are the main adverse events associated with implantable contraceptives. Other minor risks relate to the insertion and removal procedures, which require adequately trained providers as well as aseptic techniques. Furthermore, since initiation and discontinuation of use is provider-dependent and not controlled by the user, there may be a risk of coercion of use on the one hand or, on the other hand, difficulty in access to initiating use, if trained providers are not readily available. Although no single contraceptive method is perfect or appealing to all, contraceptive implants are safe and fulfil a very important need among fertility regulation methods.

Injectable hormone contraception and bone density: results from a prospective study

BACKGROUND

Depot medroxyprogesterone acetate (DMPA) injectable contraception may decrease bone density and increase the risk for osteoporosis in later life. Prospective data are scarce, especially of the effects of DMPA discontinuation on bone.

METHODS

Between 1994 and 1999, we conducted a population-based prospective cohort study among women enrollees of a Washington State health maintenance organization. We enrolled 457 nonpregnant women, ages 18-39 years (183 DMPA users and 274 non-users). Bone density was measured by dual-energy x-ray absorptiometry every 6 months for 3 years.

RESULTS

Bone density decreased notably among DMPA-exposed women at the spine (adjusted mean bone density was -0.0053 gm/cm for DMPA users compared with +0.0023 gm/cm for non-users for each 6-month interval) and total hip (-0.0060 compared with -0.0002 gm/cm ). This represents an annualized mean rate of change at the spine of -0.87% compared with +0.40% and, at the hip, -1.12% compared with -0.05%. Discontinuers of this method (N = 110) showed sizable increases in bone density over comparison women (for each 6-month interval, adjusted mean spine bone density was +0.0067 gm/cm compared with +0.0023 gm/cm, respectively; adjusted mean hip bone density was +0.0035 compared with -0.0002 gm/cm ). Estimated annualized mean rates of change were +1.41% compared with +0.40% [corrected] at the spine and +1.03% [corrected] compared with -0.05% at the hip. After 30 months, mean bone density for discontinuers was similar to that of non-users.

CONCLUSIONS

In this study, DMPA use was strongly associated with bone density loss. Substantial postdiscontinuation recovery of bone provides evidence that the effects may be largely reversible.

Bone mineral density in adolescent and young Thai girls receiving oral contraceptives compared with depot medroxyprogesterone acetate: a cross-sectional study in young Thai women

This cross-sectional study of bone mineral density in adolescent and young Thai girls receiving oral contraceptives compared with depot medroxyprogesterone acetate was performed to evaluate the differences among these groups. Thirty current OC users and 30 current depot medroxyprogesterone acetate (DMPA) users were included in the study. The mean duration of OC use was 28.8 +/- 3.4 months and of DMPA 24.6 +/- 3.3 months. Dual energy X-ray absorptiometry (DEXA) was used to measure bone mineral density (BMD) at distal and ultradistal forearm of the nondominant side. The BMD of ultradistal forearm of OC users and that of DMPA users were 0.423 +/- 0.048 and 0.403 +/- 0.039 g/cm(2) and at distal forearm of OC and DMPA users were 0.566 +/- 0.043 and 0.571 +/- 0.064 g/cm(2), respectively. However, there were no statistical differences in BMD in these two groups.

Bone mineral density at various anatomic bone sites in women receiving combined oral contraceptives and depot-medroxyprogesterone acetate for contraception

The association between users of combined oral contraceptives and depot-medroxyprogesterone acetate (DMPA) for contraception and bone mineral density (BMD) has been controversial because of variations among studies. Like other studies, this cross-sectional study compares BMD in users of combined oral contraceptives and DMPA with that in nonusers. Unlike previous studies, we defined long-term use as >2 years, and we measured more bone sites than previous studies including lumbar spines, femurs, and forearms. The study group consisted of 59 women aged 30 years to 34 years who had been using combined oral contraceptives for 57.36 +/- 27.02 months with a minimum period of 24 months, 34 women of the same age who had been using DMPA as contraceptive for 55.76 +/- 35.31 months, and 62 women of the same age who had not used any steroid hormonal contraceptives for more than 6 months. BMD was measured by dual energy photon absorptiometer at lumbar spine 2-4, neck of femur, Ward's triangle of femur, greater trochanter of femur, ultradistal radius, and distal ulnar, respectively. Age, body mass index, and lifestyles of both groups were matched with nonusers. Mean BMD at lumbar spine (L2-4) in the DMPA users was significantly lower than in the controls (1.031 +/- 0.090 vs. 1.096 +/- 0.116, p = 0.007). There were no significant differences in BMD values at bone sites other than lumbar spine between DMPA users and the controls. There were no significant differences in BMD values at all bone sites between combined oral contraceptives users and the controls. We conclude that combined oral contraceptives are not associated with changes in values of BMD, while DMPA is associated with decreased BMD only at lumbar spine. We comment that steroid hormonal contraceptives are safe to use for long-term contraception regarding bone mass effects.

Safety of implantable contraceptives for women: data from observational studies

Contraceptive implants are registered in over 60 countries and have been used by millions of women for three decades. This article reviews findings from observational studies on the safety of contraceptive implants and examines the risk of specific health outcomes. Fifty-five articles were reviewed, and the body of evidence for each health outcome was summarized. Available evidence suggests that contraceptive implants are safe and, overall, implant users do not experience adverse events at rates higher than women not using implants. With respect to specific outcomes, the evidence suggests no increased risks of pelvic inflammatory disease, decreased bone mineral density, anemia, thrombocytopenia, or death with implant use. The evidence was too limited to draw meaningful conclusions for neoplastic disease, cardiovascular events, and HIV/AIDS. Nonsignificantly elevated associations were reported for diabetes, serious mental disorders, and rheumatoid arthritis. Conditions for which risks were marginally, yet significantly, elevated were hypertension and gall bladder disease.

Depot medroxyprogesterone and bone mineral density

OBJECTIVE

To investigate depot medroxyprogesterone (DMPA)-associated bone loss in a general practice setting.

DESIGN

Forty-eight patients from a single practice who had used DMPA for contraception for more than 2 years. All patients had a serum oestradiol and if the serum level was <52 pmol/l or >52 pmol/l with menopausal symptoms, bone mineral densitometry (BMD) measurements were made at the lumbar spine (LS) and femoral neck (FN) using dual-energy x-ray absorptiometry (DEXA). Thirty-two patients had bone densitometry, of whom 27 had a serum oestradiol <52 pmol/l and five >52 pmol/l associated with menopausal symptoms. Of the remaining 16 patients, nine patients had a serum oestradiol <52 pmol/l but did not have a BMD as they moved away (five women) or switched to another contraceptive (four women).

RESULTS

BMD results showed a significantly reduced bone mass at both sites with mean Z score LS -0.84 (95% CI -1.17 to -0.52) and FN -0.32 (95% CI -0.62 to -0.02). Eighteen women (56% of 32 women) had either osteopenia (15 cases) (T score < -1.0) or osteoporosis (three cases) (T score < -2.5) at the LS. There were trends to an association of a family history of height loss or tobacco smoking (current or past) for LS and FN Z scores that did not quite achieve significance. There was also a trend to lower body weight in those with a possible family history of osteoporosis or who were smokers and an inverse correlation of weight with BMD at the FN (p < 0.05) and a non-significant inverse correlation at the LS.

CONCLUSION

The present results demonstrate that a low bone mass should be considered in patients with prolonged DMPA usage especially if they have risk factors for osteoporosis.

Overview of the relationship between use of progestogen-only contraceptives and bone mineral density

OBJECTIVES

To summarise the available epidemiological evidence regarding the relationship between the use of progestogen-only contraceptives and bone mineral density.

DESIGN AND METHODS

Overview of the published epidemiological literature.

RESULTS

Overall, 17 studies of the use of progestogen-only contraceptives and bone mineral density were identified, involving 1529 women exposed to progestogen-only contraceptives and 2086 controls. Sixty-eight percent of the data relate to the effects of use of depot medroxyprogesterone acetate. Average bone mineral density was reduced in current users of depot medroxyprogesterone acetate compared with non-users, although density in users was within one standard deviation of the mean in non-users. There was significant heterogeneity between the results of different studies (P < 0.0001). The reduction in bone mineral density appeared to be greater at the lumbar spine, femoral neck and ultradistal forearm than at the midshaft of the ulna. Studies involving women with a longer average duration of use of depot medroxyprogesterone acetate displayed greater reductions in bone mineral density compared with studies of women with shorter durations of use. Based on limited data, no difference in bone mineral density was observed between former and never users of depot medroxyprogesterone acetate. Results regarding the effect of levonorgestrel implants were conflicting. Studies of progestogen-only oral contraceptives and the progesterone vaginal ring were small and restricted to lactating women.

CONCLUSIONS

Women currently using depot medroxyprogesterone acetate have a lower average bone mineral density than non-users. The magnitude of this effect is uncertain but appears to be greater with longer durations of use.

Efficacy and side effects of Norplant use in Thai women above the age of 35 years

A prospective study of Norplant implant use in women aged above 35 years was conducted in Bangkok, Thailand. The purposes of this study were to evaluate the efficacy, menstrual patterns, and side effects of Norplant use in these women. A total of 100 women were recruited in a 1-year clinical study. Their mean age was 39.7 years. Most acceptors had completed secondary school. No accidental pregnancy occurred throughout the 1 year of use in this study. The most common menstrual pattern in these acceptors was amenorrhea followed by irregular bleeding. The major side effect was irregular bleeding. There was no significant change in systolic and diastolic blood pressure during the 1 year follow-up period. Thus, Norplant implant use in older women is a safe and effective contraceptive method. This should become another choice for contraception in women aged above 35 years who have contraindications for oral contraceptive use.

Magnitude and variability of sequential estradiol and progesterone concentrations in women using depot medroxyprogesterone acetate for contraception

OBJECTIVE

To describe the magnitude and variability of sequential serum estradiol and progesterone concentrations throughout one depot medroxyprogesterone (DMPA) injection interval.

DESIGN

Prospective study.

SETTING

Family planning and women's health clinics.

PATIENT(S)

Thirty-one women, ages 19 to 46, using DMPA for contraception.

INTERVENTION(S)

Serum for estrogen and progesterone was collected weekly throughout one DMPA injection interval.

MAIN OUTCOME MEASURE(S)

Serum estradiol and progesterone concentrations; estradiol patterns produced from data plotted across the entire DMPA injection interval.

RESULT(S)

The average daily estradiol concentrations ranged from 7.9 to 69.1 pg/mL, with a mean of 18.9 +/- 12.9 and a median of 15.4 pg/mL. Average daily progesterone concentrations ranged from 0.14 to 1.1 ng/mL, with a mean of 0.40 +/- 0.19 ng/mL and a median of 0.36 ng/mL. Two general patterns of estradiol concentrations were identified. One pattern, observed in approximately one third of the participants, reflected estradiol concentrations that were extremely low (mean, 12.7 +/- 3.6 pg/mL; median, 13.4 pg/mL) and consistently flat across the DMPA injection interval. The second pattern, seen in the remaining participants, reflected estradiol concentrations that were higher (mean, 22.2 +/- 14.9 pg/mL; median, 17.3 pg/mL) and quite variable.

CONCLUSION(S)

This study demonstrated that estradiol concentrations were lower than the 40 to 50 pg/mL reported in most studies and, for the majority of women, varied substantially across the DMPA injection interval.

Implantable contraception

Although levonorgestrel contraceptive implants have been available for over 15 years, innovations have only recently led to a wider choice. These new implants offer easier insertion and removal and other advantages depending on the type of progestin. Implants prevent pregnancy by several mechanisms, including inhibition of ovulation and luteal function and alteration of cervical mucus and the endometrium. The high efficacy and ease of maintenance make implants an ideal contraceptive for many women, including adolescents, a population that uses implants infrequently but reports high satisfaction. Implants are appropriate for women who are breastfeeding, who have contraindications to estrogen, or who have diseases such as diabetes, hypertension, sickle cell anemia, or an HIV infection because implants have few metabolic or hematologic effects. Long-term use has not been associated with a decrease in BMD and generally leads to increased blood levels and iron stores. Women who wish to space their pregnancies appreciate the nearly immediate onset of action with insertion and the rapid termination of all effects with removal. All types of implants lead to menstrual changes and other side effects in some women. Adverse effects that occur in implant users more than the general population include headaches and acne. Women must be thoroughly counseled regarding the potential for menstrual alteration, side effects, and sexually transmitted infections if they do not use condoms. Despite their initial high cost, implants are a cost-effective method over several years, even when discontinued before the life of the implant.

Injectable contraception. New and existing options

DMPA and MPA/E2C contraception offer women safe, effective, convenient, and reversible birth control choices. The use of DMPA, a 3-month injectable, is characteristically associated with amenorrhea. Lactating women and women in whom contraceptive doses of estrogen are contraindicated can use this progestin-only birth control method. Return of fertility can be delayed in women discontinuing DMPA to become pregnant. In some cases, the use of DMPA also confers important noncontraceptive and therapeutic benefits. A monthly estrogen/progestin injectable contraceptive, MPA/E2C should appeal to women who are concerned about daily pill taking, who prefer regular cycles to amenorrhea, and who find monthly injections acceptable and accessible. As is true for oral contraceptives, MPA/E2C represents an appropriate choice for women who prefer a rapidly reversible contraceptive. Currently, the proposed contraindications for MPA/E2C parallel those for combined oral contraceptives. As MPA/E2C contraception becomes available for American women, clinicians will learn how to best include this new method among the array of contraceptive choices. By individualizing contraceptive selection, counseling, and management approaches based on the relevant behavioral and medical considerations reviewed herein, clinicians can maximize their patients' success with injectable contraceptives. The more innovative that clinicians, family planning agencies, and insurers are in facilitating access to care (including reinjections), the more women will be able to avail themselves of safe, effective, and reversible methods of contraception. In addition to the physician's office or health clinic, other sites at which women might receive contraceptive injections include employee health clinics, college health clinics, or perhaps the pharmacy where the prescription is filled. Self-administration may become an appropriate option for some users of injectable contraception.

Adolescents: at increased risk for osteoporosis?

Perhaps the most important factor in the primary prevention of osteoporosis is the attainment of an optimal peak bone during adolescence. In addition to endogenous factors, such as genetic and ethnic background, environmental factors such as dietary habits, physical activity, and sex hormone therapy, influence the accretion of bone mass during this critical period of skeletal growth. First, calcium dietary intake in adolescents is generally well less than the current recommended RDA of 1200 mg/day. Multiple studies of children and adolescents have demonstrated increases in bone mass with dietary calcium supplementation. Second, regarding physical activity, the overall impression is that a moderate amount of particularly weight-bearing exercise has a positive impact on bone. There appears, however, to be a threshold of intensity of physical activity over which a negative impact on bone occurs, particularly when the exercise is of an anaerobic nature or occurring in very thin, amenorrheic participants. Third, previous research suggests that the various forms of hormonal contraception exert differing effects on bone mass in adolescents, with levonorgestrel implants and combined oral contraceptives may be associated with a more positive effect on bone mass compared with that observed with depot medroxyprogesterone acetate. From a clinical perspective, approaches to optimizing peak bone mass in adolescents would include increasing calcium intake, whether in the form of dairy products, fortified foods, or supplements as well as encouraging participation at a moderate level, in weight-bearing exercise. Last, in adolescents with extensive risk factors and predicted long duration of use, subdermal implants or combined oral contraceptives may be the optimal hormonal methods of birth control.