Serum LH Concentration in Women under Contraceptive Treatment with Estrogen-Free Progestagens

Abstract

Serum LH levels were measured by a radioimmunoassay technique throughout the menstrual eycle in 17 untreated healthy women, 19 women on norethindrone enanthate (200 mg intramuscularlyevery 12 weeks) and 10 women receiving a continuous dose of 0.03 mg d-norgestrel daily. All the controls showed a midcycle peak which represented a 4.0 to 16.3-fold increase of the values observed du ring the proliferative phase. During the fust four weeks after injection of norethindrone enanthate LH levels were depressed. Small midcycle rises were observed in only 2 cases. They represented 4.4 and 8.8-fold increase of the basal LH concentration. From the 4th to the 12th week a progressive increase in LH values was observed. During the last month of treatment the LH concentration was even higher than in the cQntrols, with the presence of moderated midcycle peaks. In the d-norgestrel group, 9 of 10 subjects showed significant but diverse LH rises. LH peaks in these women appeared earlier than in controls, the length of the menstrual cycle was also shorter. During the first and second part of the cycle women on d-norgestrel have signifieantly higher values than controls but the maximum midcycle elevations were less pronounced.