***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: 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 r and omly 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 BACKGROUND This Phase 3 , r and omized , open-label , multicenter study conducted at 44 sites in Europe evaluated the safety and efficacy of a continuous , daily regimen of levonorgestrel ( LNG ) 90 mcg/ethinyl estradiol ( EE ) 20 mcg compared with a 21-day , cyclic LNG 100 mcg/EE 20 mcg regimen . STUDY DESIGN Three hundred twenty-three healthy women were r and omized to continuous LNG 90 mcg/EE 20 mcg and 318 subjects to cyclic LNG 100 mcg/EE 20 mcg for 1 year  ( 13 pill packs ) . Pearl index , adverse event ( AE ) incidence and bleeding profiles were assessed . RESULTS No pregnancies occurred with the continuous oral contraceptive ( OC ) ( Pearl index=0.00 ) . As the study progressed , the percentage of women who achieved amenorrhea during each 28-day pill pack increased : 40 % at pill pack 7 , 53 % at pill pack 13 . The percentage of women with no bleeding [ with or without spotting ( defined as not requiring sanitary protection ) ] was 50 % , 69 % and 79 % at pill packs 3 , 7 and 13 , respectively . The incidence of AEs was similar to that of the cyclic OC ( except for metrorrhagia and vaginal bleeding in the first 6 months ) . CONCLUSIONS Continuous LNG 90 mcg/EE 20 mcg was shown to be a safe and effective OC in this direct comparison to a cyclic OC . Suppression of menses and the potential for no bleeding requiring sanitary protection may be provided by this continuous , low-dose OC 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 , werer and omly 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 OBJECTIVE The purpose of this clinical trial was to evaluate the effect of estrogen supplementation on bone mineral density in adolescent girls who received depot medroxyprogesterone acetate for contraception . STUDY DESIGN One hundred twenty-three adolescents who began receiving depot medroxyprogesterone acetate injections every 12 weeks were assigned r and omly to receive monthly injections of estradiol cypionate or placebo . The main outcome was bone mineral density that was measured by dual energy x-ray absorptiometry for 12 ( n = 69 ) to 24 ( n = 36 ) months . Participants , technicians , and physicians were blinded to estrogen treatment . RESULTS Over the 24-month period , the percentage of change from baseline bone mineral density at the lumbar spine was 2.8 % in the estradiol cypionate group versus -1.8 % in the placebo group ( P < .001 ) . At the femoral neck , the percentage of change from baseline bone mineral density was 4.7 % in the estradiol cypionate group versus -5.1 % in the placebo group ( P < .001 ) . CONCLUSION Our results suggest that estrogen supplementation is protective of bone in adolescent girls who receive depot medroxyprogesterone acetate injections 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 r and omized 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 BACKGROUND A formulation of depot medroxyprogesterone acetate ( DMPA ) has been developed that allows subcutaneous injection ( 104 mg/0.65 mL ; DMPA-SC ) and achieves highly effective contraception with a similar tolerability profile to intramuscular DMPA ( 150 mg/mL ; DMPA-IM ) . STUDY DESIGN This r and omized , evaluator-blinded study was design ed to compare efficacy , safety , and user satisfaction in women receiving DMPA-SC ( n=266 ) or DMPA-IM ( n=268 ) for 2 years with an option to continue for a third year . The primary objectives were to evaluate bone mineral density ( BMD ) changes and contraceptive efficacy after 2 years . RESULTS A total of 225 women completed the first 2 years of this study ( DMPA-SC , n=116 ; DMPA-IM , n=109 ) . After 2 years of DMPA use , BMD loss was marginally smaller in the DMPA-SC group than in the DMPA-IM group at both the total hip ( -3.3 % and -3.6 % , respectively ) and lumbar spine ( -4.3 % and -5.0 % , respectively ) . In those women who received DMPA during the third year , there were no statistically significant differences in BMD loss between DMPA-SC and DMPA-IM groups at the end of Year 3 . Recovery of BMD was observed in the small sub population of women who had discontinued DMPA-SC or DMPA-IM after the second year . The 2-year treatment-failure cumulative pregnancy rate was 0 % in the DMPA-SC group and 0.8 % ( 95 % confidence interval , 0.00 - 2.37 % ) in the DMPA-IM group ( life-table method ) . Adverse events were similar in the two groups except that injection site reactions were more common in the DMPA-SC group . CONCLUSION DMPA-SC is an effective and well-tolerated contraceptive option , providing comparable efficacy and BMD safety to DMPA-IM BACKGROUND Several studies , including an earlier analysis from the Royal College of General Practitioners ( RCGP ) Oral Contraception Study , have suggested that ever users of oral contraceptives have an increased risk of fracture when compared with never users . In this paper , we examined a subset of women in the RCGP study living in Scotl and to determine whether this risk has persisted . STUDY DESIGN A nested case-control study was carried out using data collected prospect ively for the RCGP Oral Contraception Study . Cases were women with a first ever diagnosis of fracture ( n=651 ) , age-matched to two controls ( n=1302 ) . Adjustments were made for smoking , social class and parity . RESULTS There was not a significant association between ever use of oral contraception  and fracture ( adjusted odds ratio 1.05 , 95 % confidence interval 0.86 - 1.29 ) , compared with never users . Neither were significant associations found between fracture and smoking , social class and parity . The findings did not vary material ly with age or type of fracture . CONCLUSION Ever use of oral contraception was not associated with fracture in this study 2 preparations of a sequential oral contraceptive containing 11 tablets of .1 mg mestranol and 10 tablets of .1 mg mestranol and 2 mg chlormadinone were compared : 127 women took the pills with 7 placebos ( Eunomin ) for 848 cycles and 47 women took them without placebos  ( GC 527 ) for 267 cycles . 1 pregnancy occurred due to patient error . No differences were recorded in weight changes , bone symptoms , breakthrough bleeding , breast symptoms , or increased libido . Mucorrhea and constipation were more common with the placebos . The side effects of nausea , nervousness , headache , fatigue , and decreased libido were frequent with placebos . 19.8 % discontinued Eunomin , while 23.4 % stopped taking CG 527 . 76.9 % of the women on Eunomin and 65.2 % of those on CG 527 did not have the side effects that they had experienced with previou s pills The question of differential effects on bone density by two different types of progestogen-only methods for contraception in premenopausal women was addressed . Data from a prospect i ve r and omized clinical trial among 22 premenopausal women , age 32.6 ( range 20 - 45 years ) , who were r and omly assigned to either of two treatments with continuous progestogens for contraception were analyzed ; depot-medroxyprogesterone acetate ( DMPA ) or continuous levonorgestrel treatment with subdermal implants ( Norplant ) , respectively . Forearm bone density ( BMDprox ) increased with 2.94 % ( p = 0.006 ) in women who were prescribed levonorgestrel , which was in contrast to stable values in those prescribed depot-medroxy-progesterone acetate ; group difference at 6 months for BMDprox 3.4 % ( 95 % CI 1.3 , 5.5 ; p = 0.025 ) and BMDdist 4.1 % ( 95 % CI - 1.3 , 9.6 ; p = 0.077 ) . The changes in bone density were consistent with the changes in biochemical indices for bone metabolism ;  DMPA users showed signs of increased bone turnover and users of levonorgestrel showed increased bone formation with increased levels of both alkaline phosphatase ( p = 0.004 ) and osteocalcin ( p = 0.007 ) . The findings suggest an increase in bone density during treatment with levonorgestrel and stable values during short-term administration of DMPA , in st and ard clinical doses for contraception INTRODUCTION Prior studies have suggested that oral contraceptives ( OCs ) may be associated with an increased fracture risk . However , the previous studies have only performed a limited adjustment for other potential risk factors . SUBJECTS AND METHODS All women with a fracture ( n=64,548 ) in the year 2000 in Denmark served as cases . For each case , three age-matched controls were r and omly drawn from the general population ( n=193,641 ) . Exposure was use of OCs between January 1 , 1996 , and December 31 , 2000 . Adjustments were made for use of other drugs , pregnancy , prior fracture , other diseases and social variables . RESULTS In the unadjusted analysis , use of OCs 
    Output:
    
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 .
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 .
For example , injectable contraceptives and implants provide effective , long-term birth control yet do not involve a daily regimen .