Oral contraceptive absorption and sex hormone binding globulins in obese women: effects of jejunoileal bypass

Plasma levels of two oral contraceptive gestagens were studied during 24 hour oral challenges in seven morbidly obese women after jejunoileal bypass comparing the results to unoperated normal controls. To study binding and transport of the gestagens, sex hormone binding globulin levels were determined in these patients, in normal-weight controls, and in unoperated morbidly obese patients. The unoperated morbidly obese patients had significantly decreased levels of sex hormone binding globulin, compared to normal-weight controls and to the jejunoileal bypass patients, whose levels were similar to the controls. The jejunoileal bypass patients had a reduced capacity to absorb oral contraceptive gestagens, although the plasma levels were of the same magnitude found in normal subjects using lower doses of gestagens. However, the gestagen to sex hormone binding globulin ratio was lower in jejunoileal bypass patients, implying reduced biologic activity and thus reduced contraceptive efficiency of the gestagen. There were no enzymatic or morphologic signs of liver dysfunction. No correlations were found between plasma gestagen levels and number or volume of stools, fecal fat excretion, or intravenous C-cholic acid load. It is concluded that caution must be exercised in prescribing oral contraceptives to jejunoileal bypass patients.