Serum bile acids during biphasic contraceptive treatment with ethinyl estradiol and norgestrel

Twenty-nine women were treated with biphasic combined oral contraceptive pills containing ethinyl estradiol 0.05 mg and levonorgestrel 0.050-0.125 mg. Serum primary bile acids (cholic acid and chenodeoxycholic acid) and one secondary bile acid (deoxycholic acid) were measured by radioimmunoassay. The serum samples were collected before the treatment and at one, three and twelve months during the treatment. No significant changes were found in these bile acid levels during the treatment. The ratio of cholic/chenodeoxycholic acid did not change either. No pathological values were found in the conventional liver function tests although serum alanine aminotransferase activity was significantly increased after twelve months' treatment. It can therefore be concluded that the present contraceptive pill does not cause any liver dysfunction detectable by bile acid measurements of other "classical" liver function tests.