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Injections for ovulation in PCOS
When a woman with PCOS does not ovulate on tablets such as letrozole, egg-growth injections (FSH or HMG) can be used. In PCOS the ovaries can over-respond, so the injections are started at a low dose and raised slowly, with frequent scans, aiming for one or two eggs only.
Watch the videos
In these videos our fertility specialist shows how egg growth is followed on the scan when injections are used in PCOS.
When are injections used in PCOS?
- When ovulation does not happen on tablets.
- When tablets give ovulation but no pregnancy after several cycles, in some cases.
- Combined with timed intercourse or IUI.
Why low-dose FSH in PCOS?
The ovaries in PCOS hold many small follicles, and they can respond to injections all at once. A low starting dose that is increased in small steps lets one follicle lead while the others stay quiet. This is often called a step-up approach.
Egg growth with injections in PCOS: the scans
Scans every few days show how many follicles are growing and how fast. When more follicles grow than planned, the doctor may stop that cycle or switch the plan to IVF, so that twins or triplets and over-stimulation are less likely. When one or two follicles are ready, a trigger injection times ovulation for intercourse or IUI.
Risks to know about
- Twins or more, if several eggs are released.
- Over-stimulation of the ovaries (OHSS): seek help at once for a swollen, tight belly, breathlessness or passing very little urine.
A typical injection cycle in PCOS
- A scan in the first days of the period, to rule out cysts and confirm a thin lining.
- Daily low-dose injections, starting early in the cycle, or after a period brought on by tablets.
- A first check scan after about a week; if no follicle has started to grow, the doctor increases the dose a little at a time.
- Scans every few days once a follicle starts to grow.
- A trigger injection when one or two follicles are mature.
- Timed intercourse or IUI over the next day or two.
Because the ovaries in PCOS can respond slowly and then suddenly, a cycle can take longer than in other women, sometimes two weeks or more of injections.
Looking after yourself during treatment
- Even a modest weight loss, when weight is high, can help ovulation and make the injections work better.
- Regular exercise and a diet with fewer refined sugars help the insulin resistance that often comes with PCOS.
- Metformin is sometimes added by the doctor; take it only if prescribed.
- Keep all scan appointments; they are what keep the treatment safe.
If the injections do not work
If no follicle grows despite careful dose increases, or too many grow cycle after cycle, the doctor may suggest another approach. Options include laparoscopic ovarian drilling in some women, or IVF, where the number of eggs can be controlled more closely and embryos can be frozen to lower the risk of over-stimulation. The choice depends on your age, the tubes, the semen report and how many cycles have been tried.
Questions to ask your doctor
- How many follicles are you aiming for in my cycle?
- What will you do if more follicles grow than planned?
- How many injection cycles do you suggest before IVF?
Tablets first, then injections
For most women with PCOS who are not ovulating, tablets come first. Letrozole is the usual first choice, and clomiphene is another option. If ovulation still does not happen after the dose has been adjusted over a few cycles, or if it happens but pregnancy does not follow after several cycles, injections are considered. Before injections, the tubes and the semen report are usually checked, so that the treatment has a fair chance. Read more about ovulation induction with tablets.
Lining and ovulation in PCOS
Periods may be irregular for months in PCOS, so a course of tablets to bring on a period is sometimes given, after a pregnancy test, before treatment begins. The scan checks both the follicle and the womb lining during the cycle.
Please do not use these injections without a doctor's plan and scans. Read more about PCOS treatment for getting pregnant and ovulation induction.
Questions about injections for PCOS
What if I do not ovulate on letrozole?
Your doctor may adjust the tablets or move to low-dose egg-growth injections with close scans.
Why are injections started at a low dose in PCOS?
The ovaries in PCOS can over-respond. A low dose raised slowly aims for one or two eggs and lowers the risk of OHSS and twins.
How often are scans done with injections?
Usually every few days, and more often as the follicles near ovulation size.
What if the scan shows more follicles than planned?
The doctor may stop that cycle or switch the plan to IVF, to lower the chance of twins or more and of over-stimulation.
Are injections or IVF better for PCOS?
It depends on age, the tubes, the semen report and how earlier treatment went. Your doctor explains which suits you.
Does weight loss help in PCOS?
When weight is high, even a modest loss can help ovulation and make the injections work better.
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What you read here explains fertility care in general terms and cannot replace a consultation. Decisions about your own care should be made with a doctor who knows your history and has seen you. We do not carry out or offer sex determination of any kind, which is prohibited by law in India under the PCPNDT Act.