PLASMA LH AND FSH CONCENTRATIONS IN WOMEN DURING AND AFTER INTERRUPTION OF CONTRACEPTIVE TREATMENT

Abstract

Plasma LH and FSH have been measured by radioimmunoassay in 59 subjects taking contraceptives for 1-8 months divided in 3 groups: 1) 25 women under 2.5 Lynestrenol + Mestranol (.075 mg) 2) 22 women under .5 mg Norgestrel + .05 Ethynil Oestradiol and 3) 12 women under various drugs. In 20 of them LH and FSH were determined during Cycle 1 after interruption of the drugs. Measurements were made on Cycle Days 8 12 13 14 and 20. No LH and FSH peaks were observed in the 3 groups. However in 16% of the cases the treatment was followed by a sudden and important release of LH but not of FSH on Days 8 12 13 or 20 but mainly on Day 12 and only in the course of 1 cycle. The mean plasma LH values in the 3 different groups are not significantly different. Mean plasma LH and FSH values in the 3 groups (without the 16% above-mentioned) are in IInd IRP HMG: Day 8 LH: 9.5 + or - 1.6 mU/ml FSH: 15.3 + or - 5.2; Day 12 LH: 6.4 + or - 1.1 mU/ml FSH: 11.7 + or - 5.5; Day 13 LH: 6.5 + or - 1.1 mU/ml FSH: 7.3 + or - 2.2; Day 14 LH: 4.6 + or - .9 mU/ml FSH: 7.6 + or - 1.5; Day 20 LH: 3.7 + or - .8 mU/ml FSH: 5.8 + or - 2.3. After interruption of contraceptives taken during 8-13 months LH and FSH measured in the course of the first cycle have shown only in about 1/3 of the subjects a normal LH and FSH peak. Thus inhibition of LH and FSH secretion occur independently of the contraceptive drug used. A normal cycle with ovulation is observed in only 1/3 of the subjects during the first month after interruption of the drug. (FULL TEXT)