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 .
A randomized cross-over study on various hormonal parameters of two triphasic oral contraceptives.
The effect of two triphasic oral contraceptives ( Triquilar [ TRQ ] and Trisiston [ TRS ] ) containing ethinyl estradiol ( EE ) and levonorgestrel ( LNG ) on various hormonal parameters was investigated in 26 women during a cross-over study .  TRS consisted of 0.03 mg EE + 0.05 mg LNG ( six tablets ) , 0.04 mg EE + 0.075 mg LNG ( six tablets ) , and 0.03 mg EE + 0.15 mg LNG ( nine tablets ) , whereas TRQ was different in the second phase ( five tablets ) and third phase ( 10 tablets ) . Blood sample s were taken on days 6 , 11 , 21 , and 28 of the control and washout cycles and the third treatment cycle . Both formulations inhibited ovulation reliably and decreased the serum levels of gonadotropins , free testosterone , and dehydroepi and osterone sulfate in a time-dependent manner , whereas estradiol and testosterone were already suppressed on day 6 , indicating a direct suppressive effect on ovarian steroid synthesis . Prolactin , which rose sporadically in some women , was not significantly changed . In contrast , the levels of sex hormone binding globulin , corticosteroid binding globulin , and cortisol were significantly elevated by 100 % . During the hormone-free interval of 7 days , all parameters returned at least partly to baseline . There was no significant difference between the effects of both formulations . The results suggest the possibility of a direct inhibitory effect of contraceptive steroids on ovarian steroid synthesis
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 .