However , subgroup analyses for the estrogen dose and the progestin type in relation to changes in SHBG levels did show significant differences : COCs containing second generation progestins and /or the lower estrogen doses ( 20–25 µg EE ) were found to have less impact on SHBG concentrations .
The current literature review and meta- analysis demonstrates that COCs decrease circulating levels of total T and free T and increase SBHG concentrations .
Due to the SHBG increase , free T levels decrease twice as much as total T. The estrogen dose and progestin type of the COC do not influence the decline of total and free T , but both affect SHBG .
BACKGROUND Combined oral contraceptives ( COCs ) reduce levels of and rogen , especially testosterone ( T ) , by inhibiting ovarian and adrenal and rogen synthesis and by increasing levels of sex hormone-binding globulin ( SHBG ) .
Although this suppressive effect has been investigated by numerous studies over many years , to our knowledge no systematic review concerning this issue had been performed .
Effects of continuous versus cyclical oral contraception: a randomized controlled trial.
CONTEXT Continuous oral contraception may better suppress the ovary and endometrium , lending itself to the treatment of other medical conditions . OBJECTIVE Our objective was to determine the effects of continuous vs. cyclical oral contraception . DESIGN This was a r and omized double-blind trial . SETTING This trial was performed at an academic medical center in Pennsylvania . PATIENTS A total of 62 healthy women with regular menses were included in the study . INTERVENTION Cyclical oral contraception ( 21-d active/7-d placebo given for six consecutive 28-d cycles ) vs. continuous ( 168-d active pill ) therapy using a monophasic pill ( 20 microg ethinyl estradiol and 1 mg norethindrone acetate ) was examined . MAIN OUTCOME MEASURES The primary outcome was vaginal bleeding , and secondary outcomes included hormonal , pelvic ultrasound , quality of life , and safety measures . RESULTS There was no statistically significant difference in the number of total bleeding days between groups , but moderate/heavy bleeding was significantly greater with the cyclical regimen [ mean 11.0 d ( sd 8.5 ) vs. continuous 5.2 d ( sd 6.8 ) ; P = 0.005 ] , with both groups decreasing over time . Endogenous serum and urinary estrogens measured over six cycles were significantly lower ( P = 0.02 and 0.04 , respectively ) in the continuous group than the cyclical group . Women in the continuous group also had a smaller ovarian volume and lead follicle size over the course of the trial by serial ultrasound examinations . The Moos Menstrual Distress Question naire showed that women on continuous therapy had less associated menstrual pain ( P = 0.01 ) and favorable improvements in behavior ( P = 0.04 ) during the premenstrual period . CONCLUSIONS Continuous oral contraception does not result in a reduction of bleeding days over a 168-d period of observation but provides greater suppression of the ovary and endometrium . These effects are associated with improved patient symptomatology
However , subgroup analyses for the estrogen dose and the progestin type in relation to changes in SHBG levels did show significant differences : COCs containing second generation progestins and /or the lower estrogen doses ( 20–25 µg EE ) were found to have less impact on SHBG concentrations .
The current literature review and meta- analysis demonstrates that COCs decrease circulating levels of total T and free T and increase SBHG concentrations .
Due to the SHBG increase , free T levels decrease twice as much as total T. The estrogen dose and progestin type of the COC do not influence the decline of total and free T , but both affect SHBG .
BACKGROUND Combined oral contraceptives ( COCs ) reduce levels of and rogen , especially testosterone ( T ) , by inhibiting ovarian and adrenal and rogen synthesis and by increasing levels of sex hormone-binding globulin ( SHBG ) .
Although this suppressive effect has been investigated by numerous studies over many years , to our knowledge no systematic review concerning this issue had been performed .