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.
PIP: 7 morbidly obese women, 20-44 years of age, were followed for 1-3 years after jejunoileal bypass, with particular emphasis on gestagen binding and transport. Plasma concentrations of norethisterone and levonorgestrel were compared in the study group and a control group of nonobese healthy fertile women after ingestion of 3 mg and 0.25 mg, respectively, of these gestagens. Mean plasma levels of norethisterone and levonorgestrel were lower in the obese surgical patients than in controls at 1-8 hours after ingestion; at 24 hours, there was no longer a difference. In contrast, the study subjects had sex hormone binding globulin (SHBG) concentrations that were higher than or of the same magnitude as controls. The norethisterone/SHBG ratio was significantly lower at 1-24 hours after ingestion in jejunoileostomy patients than controls and their levonorgestrel/SHBG ratio was lower at 2, 6, and 8 hours. The lower gestagen concentrations in the study subjects likely indicates that absorption or metabolism has been affected by jejunoileostomy. Thus, the use of low-dose oral contraceptives, especially low-dose gestagen-only mini-pills, is not recommended for women who have undergone jejunoileal bypass given the risk of contraceptive failure.