***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: OBJECTIVE To determine if increasing the hormone dose or eliminating the hormone-free interval improves key pharmacokinetic ( PK ) alterations caused by obesity during oral contraceptive ( OC )  use . STUDY DESIGN Obese [ body mass index ( BMI ) ≥30 kg/m(2 ) ] , ovulatory , otherwise healthy , women received an OC containing 20 mcg ethinyl estradiol (EE)/100 mcg levonorgestrel ( LNG ) dosed cyclically ( 21 days active pills with 7-day placebo week ) for two cycles and then were r and omized for two additional cycles to the following : continuous cycling ( CC , a dose neutral arm using the same OC with no hormone-free interval ) or increased dose ( ID , a dose escalation arm using an OC containing 30 mcg EE/150 mcg LNG cyclically ) . During Cycles 2 , 3 and 4 , outpatient visits were performed to assess maximum serum concentration ( Cmax ) , area under the curve ( AUC0-∞ ) and time to steady state as well as pharmacodynamics . These key PK parameters were calculated and compared within groups between baseline and treatment cycles . RESULTS A total of 31 women enrolled and completed the study ( CC group , n=16 ; ID group , n=15 ) . Demographics were similar between groups [ mean BMI : CC , 38 kg/m(2 ) ( S.D. 5.1 ) ; ID , 41 kg/m(2 ) ( S.D. 7.6 ) ] . At baseline , the key LNG PK parameters were no different between groups ; average time to reach steady state was 12 days in both groups ; Cmax were CC : 3.82±1.28 ng/mL and ID : 3.13±0.87 ng/mL ; and AUC0-∞ were CC : 267±115 h ng/mL and ID : 199±75 h ng/mL. Following r and omization , the CC group maintained steady-state serum levels whereas the ID group had a significantly higher Cmax ( p<.001 ) but again required 12 days to achieve steady state . However , AUC was not significantly different between CC ( 412±255 h ng/mL ) and ID ( 283±130 h ng/mL ) . Forty-five percent ( 14/31 ) of the study population had evidence of an active follicle-like structure prior to r and omization and afterwards this decreased to 9 % ( 3/31 ) . CONCLUSION Both increasing the OC dose and continuous dosing appear to counteract the impact of obesity on key OC PK parameters . IMPLICATION S Obesity adversely affects the pharmacokinetics of very low dose OC pills . Although the impact of these changes on OC efficacy is still under debate , PK parameters can be normalized in obese users by continuous dosing or increasing to a low-dose pill Abstract Objectives To compare variations in bone mineral density ( BMD ) and body composition ( BC ) in  depot-medroxyprogesterone acetate ( DMPA ) users and nonusers after providing counselling on healthy lifestyle habits . Methods An exploratory study in which women aged 18 to 40 years participated : 29 new DMPA users and 25 new non-hormonal contraceptive users . All participants were advised on healthy lifestyle habits : sun exposure , walking and calcium intake .  BMD and BC were assessed at baseline and 12 months later . Statistical analysis included the Mann-Whitney test or Student 's t-test followed by multiple linear regression analysis . Results Compared to the controls , DMPA users had lower BMD at vertebrae L1 and L4 after 12 months of use . They also had a mean increase of 2 kg in total fat mass and an increase of 2.2 % in body fat compared to the non-hormonal contraceptive users . BMD loss at L1 was less pronounced in DMPA users with a calcium intake ≥ 1 g/day compared to DMPA users with a lower calcium intake . Conclusions DMPA use was apparently associated with lower BMD and an increase in fat mass at 12 months of use . Calcium intake ≥ 1 g/day attenuates BMD loss in DMPA users . Counselling on healthy lifestyle habits failed to achieve its aims . Chinese Abstract 摘 要 目的 比较健康生活习惯指导对长效醋酸甲羟孕酮应用者和不用者骨密度和体成分影响的差异 。 方法 一项针对年龄在18岁至40岁妇女的探索性研究：29名用长效醋酸甲羟孕酮，25名用非激素类避孕。建议所有的参与者都养成健康的生活习惯：晒太阳，散步和摄入钙。在开始和12个月后评估骨密度和体成分。统计分析包括Mann-Whitney检验或多元线性回归分析后行t-检验 。 结果 与对照组相比，用长效醋酸甲羟孕酮12个月后，脊椎L1和L4的骨密度较低。与非激素避孕药使用者比，他们的平均总脂肪增加了2kg，并且体内的脂肪增加2.2%；每天摄入1g钙的长效醋酸甲羟孕酮组与较低钙摄入的长效醋酸甲羟孕酮组比，两组L1的骨密度丢失不太明显 。 结论 醋酸甲羟孕酮的使用与骨密度降低明显相关，并且用药12个月后脂肪含量增加。使用醋酸甲羟孕酮时，每天摄入1克钙会抑制骨质丢失。健康生活习惯的建议未能实现其目标 BACKGROUND Studies showed that hormonal fluctuations that occur over the human menstrual cycle affect energy intake and expenditure . However , little is known about the possible effects on body weight regulation that may arise when these cyclic changes are suppressed with hormonal contraceptives . OBJECTIVE The aim of this study was to examine how a progestational contraceptive drug ( depot medroxyprogesterone acetate ) affects food intake , resting energy expenditure ( REE ) , and body weight in young women . DESIGN Twenty normal-weight women were tested in a single-blind , placebo-controlled experiment . Body weight , REE , and 3-d food intake ( food provided ) were measured in the follicular and luteal phases of 2 menstrual cycles before a single injection of depot medroxyprogesterone or saline solution was administered . Measurements were also taken 4 times after injection : in the luteal and follicular phases of 2 cycles in the placebo group and 2 wk apart ( to mimic timing of the menstrual phases ) in the drug group . RESULTS Before injection , the phase of the menstrual cycle affected both energy intake and REE . The study participants consumed more energy ( 4.3 % ; P = 0.02 ) and expended more energy at rest ( 4.3 % ; P = 0.0002 ) in the luteal phase than in the follicular phase . Comparison of pre- and postinjection means showed that treatment with the contraceptive drug had no significant effects on energy intake , REE , or body weight . CONCLUSIONS This study showed that , although phases of the menstrual cycle affected energy intake and REE , depot medroxyprogesterone acetate did not alter energy intake or expenditure or cause weight gain in young women BACKGROUND Concerns about weight gain may influence contraceptive use . We compared the change in body weight over the first 12 months of use between women using the etonogestrel ( ENG ) implant , the levonorgestrel intrauterine system ( LNG-IUS ) or depot medroxyprogesterone acetate ( DMPA ) with women using the copper intrauterine device ( IUD ) . STUDY DESIGN This was a sub study of the Contraceptive CHOICE Project , a prospect i ve cohort study of 9256 women provided no-cost contraception . Women who had been using the ENG implant , LNG-IUS , DMPA or copper IUD continuously for at least 11 months were eligible for participation . We obtained body weight at enrollment and at 12 months and compared the weight change for each progestin-only method to the copper IUD . RESULTS We enrolled a total of 427 women : 130 ENG implant users , 130 LNG-IUS users , 67 DMPA users and 100 copper IUD users . The mean weight change ( in kilograms ) over 12 months was 2.1 for ENG implant users [ st and ard deviation (SD)=6.7 ] ; 1.0 for LNG-IUS users ( SD=5.3 ) ; 2.2 for DMPA users ( SD=4.9 ) and 0.2 for copper IUD users ( SD=5.1 ) . The range of weight change was broad across all contraceptive methods . In the unadjusted linear regression model , ENG implant and DMPA use were associated with weight gain compared to the copper IUD . However , in the adjusted model , no difference in weight gain with the ENG implant , LNG-IUS or DMPA was observed . Only Black race was associated with significant weight gain ( 1.3 kg , 95 % confidence interval=0.2 - 2.4 ) when compared to other racial groups . CONCLUSIONS Weight change was variable among women using progestin-only contraceptives . Black race was a significant predictor of weight gain among contraceptive users INTRODUCTION The study was conducted to assess the impact of depot medroxyprogesterone acetate subcutaneous injection 104 mg/0.65 mL ( DMPA-SC 104 ) on body weight . METHODS Changes in weight from pretreatment were analyzed using data from two 1-year , noncomparative trials of DMPA-SC 104 ( North/South American , N=722 ; European/Asian , N=1065 ) and a 3-year , r and omized study ( SC/IM ) comparing DMPA-SC 104  ( N=266 ) with the DMPA intramuscular injection 150 mg/mL ( DMPA-IM 150 ) . For each study , additional analyses were conducted for changes in body weight by age ( < 25 , 25 to 35 and > 35 years ) and body mass index  ( BMI ) ( < or=25 , > 25 to < or=30 and > 30 kg/m2 ) subgroups . RESULTS In both 1-year trials , the mean ( + /-SD ) weight gain at month 12 was < 2 kg [ 1.7 kg ( + /-4.5 SD ) in the Americas trial and 1.4 kg ( + /-3.6 SD ) in the Europe/Asia trial ] . In the SC/IM trial , mean weight changes were similar between DMPA-SC 104 and DMPA-IM 150 groups , with mean ( + /-SD ) gains at month 36 of 4.5+/-8.5 and 5.8+/-8.7 kg , respectively . Similar differences in weight gain were observed by age or baseline BMI in all studies . CONCLUSION DMPA-SC 104 was associated with modest weight gain in most women STUDY OBJECTIVE Since bone loss has been observed among adolescents on depot medroxyprogesterone acetate ( DMPA )  , a clinical population that commonly experiences weight gain , we were interested in examining the direct relationship between body weight and bone mineral density ( BMD ) in adolescents on DMPA as compared to those on oral contraceptive pills ( OC ) or on no hormonal contraception ( control ) . DESIGN Prospect i ve , Longitudinal study . SETTING Four urban adolescent health clinics in a large metropolitan area . PARTICIPANTS Postmenarcheal girls , age 12 - 18 years , selecting DMPA , OC or no hormonal contraception .  INTERVENTIONS At baseline , 6 , 12 , 18 , and 24 months , all study participants underwent  measurement of weight and BMD of the hip and spine . MAIN OUTCOME MEASURES The correlation between weight and BMD , and the correlation between change in weight and change in BMD were assessed at each time point . RESULTS Body weight was significantly ( P < 0.05 ) positively correlated with femoral neck BMD and spine BMD at each time point regardless of contraceptive method . Change in body weight at 12 and 24 months was highly correlated with change in femoral neck BMD ( P < 0.0001 ) for all treatment groups . No statistically significant correlation between change in weight and change in spine B 
    Output:
    
We found limited evidence of weight gain when using POCs .
Weight change for the POC group generally did not differ significantly from that of the comparison group using another contraceptive .
Appropriate counseling about typical weight gain may help reduce discontinuation of contraceptives due to perceptions of weight gain