Ovulation Induction
Ovulation induction, often shortened to OI, is a short course of tablets or low-dose injections that makes the ovaries release an egg in a cycle where they otherwise would not. Letrozole and clomifene are the usual tablets. Scans track the growing follicle, and you time sex to it at home.
It does one thing, and it does it very well. It fixes ovulation. It does nothing for blocked tubes, a low sperm count or an egg supply that is running down. So the people it transforms are the ones whose only problem is not ovulating, and the largest group of them by far have polycystic ovary syndrome (PCOS).
For that group it is one of the most rewarding treatments in fertility medicine. If you have spent months waiting for periods that never arrive on time, it gives your cycle a shape again. It is cheap, it is gentle, and many people conceive within a handful of cycles without ever seeing an operating theatre or a laboratory. Two things keep it safe and effective: monitoring to keep twins down, and a set number of cycles agreed before you start.
At a glance
- Also known as
- OI, letrozole cycles, clomifene (Clomid) cycles, follicle tracking with timed intercourse, low-dose gonadotrophin stimulation
- Stages
- Up to about 6 ovulating cycles, one at a time
- Appointment time
- Five days of tablets, then one to three short scans per cycle
- Back to normal
- No time off needed
- Typical cost
- $300–$1,000 per monitored cycle on tablets (United States, self-pay)
- Usually preceded by
- Ovulation Testing, Tubal Patency Testing, Semen Analysis
Figures reviewed .
On this page
Who it’s for
The core candidate is someone who does not ovulate, or ovulates only now and then, and has nothing else in the way. Irregular or absent periods are the usual clue, and ovulation testing confirms it. PCOS accounts for most of these people. Others have a thyroid or prolactin problem, which is treated directly first.
Before the first tablet, two other results should be back: open tubes on a tubal patency test, and a normal semen analysis. Skipping them is the most common way months get lost on a treatment that could never have worked.
If you already ovulate every month, OI has nothing to fix. Unexplained infertility, mild sperm problems and blocked tubes are better served by IUI or IVF. The same goes for anyone in their late thirties or beyond, where time matters more than gentleness.
Weight matters in PCOS. A modest loss brings ovulation back on its own for some people and makes the tablets work better for others. See BMI and lifestyle.
Before the first cycle
Check that the tube test and the semen analysis are both done and read, not just booked. Ovulation induction only fixes ovulation, and knowing nothing else is in the way lets you start with real confidence.
How it’s done
Letrozole is now the first choice for most people with PCOS. It is a tablet taken for five days early in the cycle, usually starting on day two or three. It lowers oestrogen briefly, the brain answers with more follicle-stimulating hormone (FSH), and a follicle is recruited. Clomifene, the older drug sold as Clomid, does the same job by blocking oestrogen receptors in the brain, and plenty of clinics still use it.
Monitoring is what separates good OI from a prescription handed over the counter. A scan around day ten to twelve counts the follicles and measures them. One or two growing is the aim. If three or more are maturing, the clinic will usually advise against sex that cycle, which is the single biggest protection against triplets.
When the lead follicle is ready, you either wait for your own surge on a home ovulation predictor kit or have a trigger injection to set the time. Sex every day or two around that window is the whole of the procedure. A day 21 progesterone blood test then confirms the egg was released.
If tablets do not produce a follicle at the highest sensible dose, the next step is low-dose gonadotrophin injections. These are the same FSH used in IVF at a fraction of the dose, raised in small steps, with closer scanning because the ovaries respond more sharply.
At the planning appointment
Ask what the clinic will do if a scan shows three or more follicles. Hearing the plan in advance, while you are calm, makes the decision easy on the day if it comes.
After ovulation induction
There is nothing to recover from. The tablets bring hot flushes, headaches or a flat mood for a few days in some people, and letrozole tends to be gentler than clomifene on mood. Mid-cycle you may feel a dull ache on one side as the follicle grows and releases. Injections add bloating and a little bruising at the injection site.
The harder part is the rhythm of it: scans on set days, sex to a timetable, and then the two-week wait. Couples I have worked with often say timed sex was the bit nobody warned them about, so it helps to treat the window as a few days of opportunity rather than a single appointment.
Ring the clinic, rather than waiting to see, if you have severe bloating, pain that builds, or breathlessness after injections.
| Cycle day 1 | Your period starts. You ring the clinic and confirm the plan for this cycle. |
|---|---|
| Days 2–7 | Five days of letrozole or clomifene, starting on day two or three. Injections instead if tablets have not worked. |
| Days 10–14 | Follicle tracking scan. One or two follicles is the aim; three or more usually means skipping that cycle. |
| Ovulation window | A surge on a home kit or a trigger injection. Sex every day or two for the next few days. |
| Day 21 or 7 days after ovulation | Progesterone blood test to confirm the egg was released. Dose adjusted for the next cycle if not. |
| Days 28–35 | Pregnancy test if your period has not come. If it has, the next cycle starts straight away. |
| After about six ovulating cycles | Review with the clinic. This is the point agreed at the start to move on to IUI or IVF. |
In the fertile window
Plan the ovulation week like a short holiday at home, with early nights and nothing that keeps either of you late at work. Timed sex is easier when it has some space around it.
Risks and complications
The risk that matters is multiple pregnancy. Clomifene raises the twin rate to somewhere around one in ten to one in twenty pregnancies, letrozole slightly less, and injections more again if they are not carefully managed. Twins carry real risks for mother and babies, which is why scanning every cycle is the standard rather than an extra.
Ovarian hyperstimulation is rare on tablets and uncommon on low-dose injections, because the doses are built to recruit one follicle, not many. Side effects of the tablets are mostly a nuisance and wear off when the course ends.
Clomifene can thin the lining of the uterus in some people over several cycles, which is one reason letrozole has taken over. Long courses of clomifene are also avoided, and clinics cap the total number of cycles.
Ovulation induction results
When ovulation is the only problem, results are good. Most people with PCOS ovulate on letrozole or clomifene, and published trials put the chance of a baby across five or six cycles somewhere in the region of a quarter to a half, with letrozole doing better than clomifene. Each ovulating cycle gives roughly the chance of a fertile couple trying naturally at the same age.
Most of those pregnancies arrive in the first three to six ovulating cycles. After that the curve flattens. That is why the number of cycles is part of the plan from the start, and why moving on at the agreed point is a success of planning, not a failure.
The other result to count is ovulation itself. A cycle where a follicle grew and the progesterone test confirmed release has done its job, even if it did not bring a pregnancy.
Alternatives to ovulation induction
If tablets do not make you ovulate, injections are the usual next step, and for PCOS some clinics offer laparoscopic ovarian drilling instead, a keyhole operation that can restore ovulation for months. See laparoscopy.
If you are ovulating on treatment but not conceiving after the agreed cycles, the answer is to add rather than repeat. IUI places washed sperm in the uterus at the same ovulation and is the natural next rung. IVF is the step above, and in PCOS it tends to work well because there are plenty of eggs to collect.
For anyone over about thirty-seven, I would agree a short run of tablet cycles before IVF. The tablets are cheap, but months are the expensive part.
IUI
Washed and concentrated sperm placed straight into the uterus through a fine catheter, timed to ovulation. No egg collection and no laboratory fertilisation, which makes it the most affordable treatment on this site and a gentle place to start.
Best for: open tubes, reliable ovulation and adequate sperm, and almost anyone starting out with donor sperm
IVF
Conventional IVF, where the ovaries are stimulated to produce a batch of eggs, the eggs are collected under sedation and mixed with sperm in the laboratory, and one embryo is transferred. The core treatment that the other pages in this group are variations on.
Best for: anyone whose tubes, sperm or time make natural conception unlikely, and who wants the treatment with the best odds per attempt
Combining ovulation induction with other treatment
Ovulation induction pairs naturally with IUI. It uses the same tablets and scans, with an insemination in place of timed sex, and many clinics move people from one to the other without changing anything else. It is also often combined with metformin in PCOS, especially where insulin resistance is part of the picture.
Ovulation induction cost
The drugs are the cheap part. Letrozole and clomifene cost little anywhere in the world, while monitoring is where the bill sits. A cycle with one or two scans and a progesterone test is a modest outlay, and a cycle on injections costs several times more because of the drug and the extra scans.
Ask whether the quote is per cycle or for a block, and whether a cancelled cycle with too many follicles is charged in full. I would also ask what the clinic charges if you move on to IUI, because the monitoring often carries over.
Bangkok clinics offer monitored cycles at a fraction of US prices. Since a cycle needs scans across two weeks, it makes most sense for people living in Thailand or staying there a while.
| Country | Self-pay | Public / insurance |
|---|---|---|
| United States Gonadotrophin cycles typically $1,500–$4,000 with drugs and scans | $300–$1,000 per monitored cycle on tablets | Often covered where fertility treatment is covered at all; many plans require it before IUI or IVF |
| United Kingdom Tablets cost little; private fees are mostly for scans | £250–£800 per monitored cycle | Widely available on the NHS for anovulation, including PCOS, usually through a gynaecology or fertility clinic |
| Europe Injection cycles cost more because of the drug | €200–€700 per monitored cycle | Commonly funded by state systems as a first-line treatment |
| Thailand Best suited to people living in Thailand, since each cycle needs scans over two weeks | $150–$500 per monitored cycle | Self-pay for international patients |
Read more: IVF
Choosing a clinic for ovulation induction
Ovulation induction is simple to prescribe and easy to do badly. What you want is a clinic that scans every cycle, not one that hands over six months of tablets and a follow-up date. Ask how often they ovulate patients on the first dose, and how many cycles they will run before recommending a change.
Ask who reads the scans and how quickly the results reach you, because the timing of sex depends on them. Ask whether they use letrozole first for PCOS, and how they step the dose up if nothing grows.
The question that reveals the most is what they do when three follicles appear. A clinic with a clear, calm answer is managing twin risk, which is the whole reason to be monitored at all.
At the consultation
Ask the clinic to say out loud how many ovulating cycles they plan before moving on. A number agreed at the start keeps the treatment purposeful and keeps you moving forward.
Frequently asked questions
Is letrozole better than clomifene?
For PCOS, trials favour letrozole for live births, and it tends to be gentler on mood and the lining. See how it's done.
Why do I need scans if I'm only taking tablets?
To see how many follicles are growing. Scans are what keep twins and triplets down. See risks.
How many cycles should I try?
Commonly up to six ovulating cycles, since most pregnancies arrive in the first few. See results.
Will it help if I already ovulate?
Usually not. It fixes ovulation and nothing else, so IUI or IVF is the better fit. See who it's for.
Can I take letrozole without a clinic?
It is prescription-only, and taking it without scans removes the main safety check on multiple pregnancy. See choosing a clinic.