Clinical and biochemical investigations of an ultra low-dose combined type oral contraceptive

Abstract

SummaryA combination of 150 μg. d-norgestrel plus 30 μ.g. ethinyl oestradiol daily was administered by the usual 21-day treatment cycle regimen to 75 young healthy women for a total of 840 cycles. There were no pregnancies, nor any serious side-effects. Cycle control was good with a mean length of 28.5 ± 3.2 days. Breakthrough bleeding occurred in 6.1 % of cycles, spotting in 7.3 % and amenorrhoea in 1.5 %. Fasting early morning blood specimens were collected from some of the women who had received 6 treatment cycles or more, and a large series of biochemical tests was conducted on plasma or serum. The results were contrasted with similar biochemical tests conducted on other women under treatment with other oral contraceptive products, each of which contained 50 μg. daily of synthetic oestrogen. Of 70 biochemical parameters examined, 33 were closer to the normal reference range in women taking the 150/30 d-norgestrelethinyl oestradiol combination than in women using the higher dose products.