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 .
Measurement of free testosterone in normal women and women with androgen deficiency: comparison of methods.
And rogen deficiency in women is increasingly recognized as a new clinical syndrome and has raised our awareness of the importance of accurate and well-vali date d measurements of serum free testosterone ( T ) concentrations in women . Therefore , we compared serum free T levels measured by equilibrium dialysis to those measured by a direct RIA ( analog method ) and to those calculated from the law of mass action ( requires the measurement of total T and SHBG ) . We also calculated the free and rogen index , 100 x T/SHBG , as a simple index known to correlate with free T. Subjects were 147 women with variable and rogen and estrogen statuses . All were studied three times in 1 month and included women 1 ) with regular menses ( estrogen positive , T positive ) , 2 ) more than 50 yr old and not receiving estrogen ( estrogen negative , T positive ) , 3 ) receiving estrogen ( estrogen positive , T negative ) , and 4 ) with severe and rogen deficiency secondary to hypopituitarism ( estrogen negative , T negative ) . Calculated values for free T using the laws of mass action correlated well with those obtained from equilibrium dialysis ( r = 0.99 ; P < 0.0001 ) . However , the agreement depended strongly on the specific assays used for total T and SHBG . In contrast , the direct RIA method had unacceptably high systematic bias and r and om variability and did not correlate as well with equilibrium dialysis values ( r = 0.81 ; P < 0.0001 ) . In addition , the lower limit of detection was higher for the direct RIA than for equilibrium dialysis or calculated free T. Free and rogen index correlates well with free T by equilibrium dialysis ( r = 0.93 ; P < 0.0001 ) , but is a unitless number without reference to the physical reality of free T. We conclude that the mass action equation and equilibrium dialysis are the preferred methods for use in diagnosing and rogen deficiency in women
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 .