Low multiple pregnancy rate in combined clomiphene citrate--human menopausal gonadotrophin treatment for ovulation induction or enhancement.

Sixty-five infertile women, 37 with anovulation, eight with ovulatory disturbances and 20 with unexplained infertility were treated by a combination of clomiphene citrate (CC) from cycle day 5 (or 3) and human menopausal gonadotrophin (HMG) begun 3 days later for induction or enhancement of ovulation. Monitoring was carried out by measuring preovulatory 17-beta-oestradiol (E2) and progesterone (P) concentrations in blood samples and by follicle measurements using ultrasound. Forty-seven pregnancies resulted with a multiple pregnancy rate of 7.7% for those completed. This incidence is very low and within the range found for CC induction and might result from the later commencement of stimulation compared with many other protocols. These results were achieved with a low incidence of ovarian hyperstimulation syndrome (2.6% per cycle). The HMG doses given were low in comparison with those found in other forms of induction. The deleterious effects of this combined mode of induction on cervical mucus and the occurrence of premature spontaneous ovulation were much less than in the sequential mode of treatment. These results suggest that combined induction treatment by CC and HMG as described offers a means of achieving low rates of multiple pregnancies a known complication in the induction of ovulation.