A COMPARISON OF THE EFFECTS OF CLOMIPHENE AND TAMOXIFEN TREATMENT ON THE CONCENTRATIONS OF OESTRADIOL AND PROGESTERONE IN THE PERIPHERAL PLASMA OF INFERTILE WOMEN

The effects of clomiphene and tamoxifen treatment on the concentrations of oestradiol and progesterone in plasma were compared in the same infertile women. Nine patients, three with anovulation and six with suspected luteal phase deficiency, were given clomiphene during 2 months and tamoxifen during 2 months. Placebo treatment was given in the month before the first drug and during a month between drug treatments. The concentrations of oestradiol and progesterone were determined by radioimmunoassay in three samples collected each month between days 6 and 8, 11 and 13, and 18 and 20. The mean concentration of oestradiol at the time of the expected pre-ovulatory rise was 0.82 nmol/l with placebo treatment, 1.20 nmol/l following tamoxifen treatment and 5.00 nmol/l after clomiphene treatment (normal menstrual cycle maximum, 2.0 nmol/l). The mean concentration of progesterone in the luteal phases reached maxima of 41 nmol/l, 47 nmol/l and >72 nmol/l, respectively (normal menstrual cycle maximum, 60 nmol/l). When the frequency distributions of hormone concentrations were examined for each treatment, clomiphene and tamoxifen were both found to alter the distribution from that of placebo treatment (Chi-square analysis), giving a larger proportion of high concentrations. In the six patients with suspected luteal phase deficiency clomiphene treatment was followed by biochemical evidence of ovarian hyperstimulation. There was no evidence of this when any of these patients were treated with tamoxifen, nor in anovulatory patients treated with clomiphene.