Clinical experience with a low dose oral contraceptive containing norethisterone and ethinyl oestradiol.
The results are presented of a clinical investigation of an oral contraceptive containing 0.5 mg norethisterone and 0.035 mg ethinyl oestradiol. The medication was administered orally as a 21-day cyclic regimen in 1,168 women. Duration of use was from 1 to 53 cycles with an overall total of 16,345 cycles. When the preparation was taken as directed, no pregnancies occurred. Three women conceived during the course of this study; however, these subjects missed 3, 2, and 1 prescribed tablets, respectively, and their pregnancies are thus judged due to patient failure. The overall pregnancy rate was 0.22 per 100 women years of use calculated as a Pearl Index. Intermenstrual bleeding (spotting and/or breakthrough bleeding) was noted primarily in the early cycles, soon tapering off to a lower and stable level. The overall cumulative cyclic incidence of amenorrhoea was 1.0%.
D000293:Adolescent; D000328:Adult; D000568:Amenorrhea / Q000139:chemically induced; D001835:Body Weight / Q000187:drug effects; D003276:Contraceptives, Oral / Q000009:adverse effects; D003277:Contraceptives, Oral, Combined / Q000009:adverse effects; D004997:Ethinyl Estradiol / Q000009:adverse effects / Q000494:pharmacology*; D005260:Female; D006801:Humans; D008598:Menstruation / Q000187:drug effects; D008599:Menstruation Disturbances / Q000139:chemically induced; D008875:Middle Aged; D009640:Norethindrone / Q000009:adverse effects / Q000494:pharmacology*; D010352:Patient Dropouts; D011247:Pregnancy
D003276:Contraceptives, Oral; D003277:Contraceptives, Oral, Combined; D004997:Ethinyl Estradiol; D009640:Norethindrone