Explain how clomifene is used to treat infertility in women who do not ovulate regularly.

Edexcel GCSE Biology (1BI0) — 7.1 Hormonal coordination · Explain · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Some women do not ovulate regularly, which reduces their chances of becoming pregnant. Clomifene is a drug that can be prescribed to help these women.

Model answer (4 marks)

Clomifene blocks estrogen receptors in the hypothalamus, so the pituitary gland thinks estrogen levels are low. This increases the secretion of FSH and LH. The higher FSH stimulates the ovarian follicle cells to mature and produce more oestrogen. The increased LH then triggers ovulation, releasing a mature egg.

Examiner tips

Use the sequence FSH→follicle maturation→LH→ovulation
Mention the hypothalamic receptor blockade to show mechanism
Keep answer concise, 4 points
Use UK spelling

Common mistakes

Confusing clomifene as an estrogen replacement rather than a receptor blocker
Omitting the role of LH in triggering ovulation
Using vague terms like "helps ovulation" without linking to FSH/LH

Mark scheme (4 marks)

Clomifene stimulates the secretion / release of more FSH (from the pituitary gland)
Clomifene stimulates the secretion / release of more LH (from the pituitary gland)
FSH stimulates follicle cells to mature / develop (and secrete oestrogen)
LH initiates ovulation / triggers the release of an egg (from the mature follicle)

Key terms in this question

clomifene