Efficacy of clomiphene citrate and cyclofenil for infertile women with normal ovulatory cycles

Despite the widespread use of clomiphene citrate (CC) for ovulation induction, the pregnancy rates (PRs) in women who take CC are less than expected based on ovulation rates. The causes of this discrepancy between the PRs and ovulation rates have been explained by the antiestrogenic effects on cervical mucus and endometrial differentiation (1). Despite these adverse effects, CC therapy is so simple and safe that it is widely administered even to normally ovulatory women in the expectation of inducing multiple ovulation and increasing the chances of conception. On the other hand, cyclofenil, which has been reported to exert less antiestrogenic activity than CC (2), is also used to treat infertile women with not only anovulatory cycles but normal ovulatory cycles. The purpose of this study was to assess whether administration of CC or cyclofenil to women with normal ovulatory cycles is beneficial. One hundred fifty-five normally ovulatory women who received treatment for infertility at Shiga University of Medical Science from June 1998 to June 1999 were recruited for this study. Patients with ovulatory disorders, such as irregular cycles, hypothalamic or pituitary amenorrhea, polycystic ovary syndrome, premature ovarian failure, and hyperprolactinemia, were excluded from the study. Patients with bilateral tubal obstruction or azoospermia were also excluded. Administration of CC or cyclofenil was withheld for a period of 3 months after the first visit while the timing of coitus was advised. Patients were advised to have sexual intercourse within 24 hours after confirmation of a positive urinary LH with a urinary LH surge detection kit (Gold-sign LH, Morinaga Nyugyo, Tokyo, Japan). Then the patients who did not conceive were sequentially allocated to three groups: a CC-treated group, a cyclofenil-treated group, and a group with no administration. Briefly, the first patient enrolled in the study was assigned to a CC-treated group, the second patient was assigned to a cyclofenil-treated group, and the third patient was assigned to a group with no administration. Then the fourth patient was assigned to the CC-treated group, and so forth.