Clomifene for ovulation induction
Clomifene increases endogenous gonadotrophin secretion by blocking negative feedback of estrogen to receptors, particularly on the hypothalamus.
Use of clomifene requires specialist guidance and monitoring; see Assessing response to ovulation induction. A typical regimen is:
clomifene 50 mg orally, once daily for 5 consecutive days. Start between days 2 to 5 of the menstrual cycle. infertility, ovulation induction clomifene
If ovulation does not occur, an increased dose of clomifene is used for the next two cycles before considering other oral drugs. Clomifene results in ovulation in 80% of users, but only 40 to 60% become pregnant; the endometrium and cervical secretions may not be as favourable for conception as with letrozole or gonadotrophins.
Blurred or double vision or visual field defects have been reported in 1 to 2% of clomifene users. These usually resolve but treatment should not be continued. Current practice is to limit clomifene use to less than 12 months because there is a possible increased risk of ovarian cancer with long-term use, although evidence for an association is insufficient1.