Clomiphene; an ovulation-stimulating medicine
Clomifene
A fertility tablet used to stimulate ovulation in some women who are not ovulating regularly.
What is Clomifene?
Clomifene is a tablet used to help some women who are not ovulating to release an egg, as a treatment for certain causes of infertility. It works by nudging the brain to send out more of the hormones that trigger the ovaries to ripen and release an egg. It is taken as a short course over a few days early in the menstrual cycle, usually for a limited number of cycles. A key point to know is that it raises the chance of twins or other multiple pregnancies, and it can cause blurred vision or other visual disturbances, which should be reported.
Education and reference only. This is a plain-language guide to Clomifene — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Clomifene is an anti-oestrogen medicine taken by mouth to encourage ovulation, the release of an egg, in women who are not ovulating regularly. It is one of the most established first treatments for this type of infertility, particularly in conditions such as polycystic ovary syndrome. It is taken as a tablet for a few days early in each menstrual cycle, usually under the guidance of a fertility or women's health team, and only for a limited number of cycles.
How it works
Clomifene gently blocks oestrogen signals in part of the brain, which makes the body think oestrogen levels are low. In response, the brain releases more of the hormones that stimulate the ovaries, prompting an egg to ripen and be released. By restoring ovulation in this way, it gives a fertilised egg the chance to lead to pregnancy. Because it stimulates the ovaries, more than one egg can sometimes be released, which is why the chance of twins is higher.
Company & origin
Originated / developed by: Generic (long-established).
A long-established fertility tablet used in the UK to help some women who are not ovulating to release an egg.
Practical use
How to take Clomifene
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take it as a short course over a few days early in your menstrual cycle, exactly as your fertility team directs.
- Follow the instructions on which cycle day to start, as this timing matters for it to work.
- Attend the blood tests or scans arranged to check whether you are ovulating and how your ovaries are responding.
- Report any blurred vision, flashing lights or spots before your eyes promptly, as treatment may need to be stopped.
- Tell your team about severe abdominal pain or marked bloating, which can be a sign of overstimulated ovaries.
- Do not continue beyond the number of cycles advised, as treatment is intended to be time-limited.
Weighing it up
Advantages & disadvantages of Clomifene
Advantages
- An effective, well-established and convenient tablet that restores ovulation in many women who are not ovulating.
- Taken as a short course each cycle rather than continuously, and is relatively inexpensive.
- Often the first step tried before more involved fertility treatments.
Disadvantages
- Clearly raises the chance of twins or other multiple pregnancies.
- Can cause visual disturbances, hot flushes, mood changes and abdominal discomfort.
- Only recommended for a limited number of cycles, and does not help everyone.
Practical use
Good to know
Clomifene is usually started early in the menstrual cycle and taken for a few days, then repeated over a small number of cycles rather than indefinitely, because benefit is mostly seen within the first several cycles. Ovulation is often tracked with blood tests or scans to check it is working and to watch the ovaries. The chance of having twins or more is noticeably higher than with natural conception, so this is discussed in advance. Visual disturbances such as blurred vision, flashes or spots can occur and should be reported promptly, as treatment may need to stop. Hot flushes, mood changes, headaches and abdominal discomfort are common, and significant bloating or pain can occasionally signal overstimulation of the ovaries, which needs checking.
Who should not take it / use with caution
- It is not used in pregnancy, and pregnancy is usually checked or excluded before each course.
- It is avoided in people with certain liver problems, unexplained vaginal bleeding or some ovarian cysts.
- It is not suitable where infertility has a cause that clomifene cannot address, so the reason is assessed first.
Monitoring
- Blood tests or scans to confirm whether ovulation is happening and how the ovaries respond.
- Watching for visual disturbances or signs of overstimulated ovaries during treatment.
- Reviewing progress after each cycle and stopping once the agreed number of cycles is reached.
Side effects
- Hot flushes, mood changes, headaches and abdominal bloating or discomfort are common.
- Visual disturbances such as blurred vision, flashes or spots can occur and should be reported.
- Rarely, marked abdominal pain and swelling from overstimulated ovaries, which needs urgent checking.
Key interactions
- It is generally taken on its own for fertility, but tell your team about all medicines and supplements you take.
- Other hormone or fertility treatments are only combined with it under specialist guidance.
- Always confirm with your prescriber before adding any new medicine while trying to conceive.
Available as: Tablets taken by mouth.
Answers
Clomifene: frequently asked questions
How does clomifene help me get pregnant?
It encourages your ovaries to release an egg by nudging the brain to send out more of the hormones that drive ovulation, which is helpful if you are not ovulating regularly.
Does it increase the chance of twins?
Yes. Because it stimulates the ovaries, more than one egg can be released, so the chance of twins or other multiples is noticeably higher than with natural conception.
Why might my vision change while taking it?
Some people get blurred vision, flashes or spots; this should be reported promptly, as treatment may need to be stopped.
How many cycles will I take it for?
It is usually used for only a limited number of cycles, as most benefit is seen early; your fertility team will advise when to stop.
Should my ovulation be monitored?
Yes, blood tests or scans are often arranged to check whether you are ovulating and to keep an eye on your ovaries.
Authoritative sources
- BNF
- NICE CKS
Building a medicines information resource?
We create evidence-led, dose-free drug and formulary references for teams.