Helping you become pregnant by ovulation induction

Read our guide below to help you understand how to become pregnant by ovulation induction.

You can also download a PDF version of this patient information by following the link on the right.

What causes ovulation problems?

Problems with ovulation happen in approximately 25% (1 in 4) of couples who have difficulty getting pregnant (1). Common causes for ovulation problems include:

• polycystic ovarian syndrome (PCOS)
• problems with the thyroid or pituitary glands
• being overweight or being underweight.

Having a BMI over 30 will also reduce the fertility of both men and women.

Women who aren’t ovulating and have a BMI over 30 should understand that weight loss can improve their chance of ovulation, conception, and pregnancy outcomes.

If you have a BMI under 19, weight gain can improve your chance of ovulation, conception, and pregnancy outcomes.

What is ovulation?

It’s the process where the ovaries release an egg. For eggs to mature and be released by the ovaries, a regular menstrual cycle is usually required.

What is ovulation induction?

It’s what we call interventions that stimulate the ovaries to release eggs. There are different options to do this.

The options we offer include:

Clomiphene citrate (clomid)

A medicine to increase fertility

Letrozole

This is a newer ovulation induction medication compared to clomid. Its use in fertility is off-licence, for example, the drug company hasn’t applied for a specific licence for letrozole to be used in ovulation induction

At this NHS Trust, we use it as a ‘second line’ medication. Your fertility team may offer it if you’ve previously didn’t respond to or couldn’t tolerate clomid.

Ovarian drilling

This is done by laparoscopic (keyhole) surgery. It has a 2 in 1,000 risk of serious complications, for example, damage to internal organs and major blood vessels (2)

It doesn’t involve medication.

How do I take the medication?

Take letrozole and clomid in the same way.

Take either letrozole or clomid once a day, on days 2, 3, 4, 5 and 6 of your cycle.

The usual starting dose is 5mg for letrozole and 50mg for clomid.

If you have irregular periods, we may give you a 5-day course of progesterone tablets (Provera 10 mg twice a day) to induce a bleed. Bleeding should start 5 to 10 days after finishing Provera.

The first day of your period. Day 1	Day 2	Day 3	Day 4	Day 5	Day 6
Call 01494 324563 to arrange a scan	Start clomid/letrozole	Continue clomid/letrozole	Continue clomid/letrozole	Continue clomid/letrozole	Take the last tablet of clomid/letrozole

Monitoring

To monitor the ovaries’ response to the medication, we do a transvaginal (internal) ultrasound scan, usually between day 11 and day 14 of your cycle.  This allows us to monitor the development of follicles in your ovaries.

If there are too many follicles, we may need to cancel the treatment cycle. We’ll adjust your subsequent medication dose due to the risk of multiple pregnancy.

We advise you not to have unprotected intercourse until you have had the scan in that cycle.

How to arrange your scan

On the first day of your period / first day of taking the medication, call the fertility secretary on 01494 324563.  This allows us to arrange an accurate timing for the ultrasound scan.

We also recommend a blood test (progesterone level) on day 21 of a 28-day cycle (or 7 days before the next expected period).  A progesterone level of 20 nmol/L or above is a good result and confirms ovulation.

Contact the fertility clinic secretary to discuss the result of the blood test.

If you have ovulated, we suggest doing a home pregnancy test 10 days after the blood test. If this is negative, start a new cycle of treatment by restarting letrozole/ clomid from day 2 of the next period.

Are there any side effects?

Letrozole and clomid are generally safe and widely used but there’s a small increase in the risk of multiple pregnancies (around 5%, compared to 1% in the normal population) (3 to 6).

Mild side effects may include:

• gastrointestinal upset (stomach ache)
• hot flushes
• headache
• back pain
• breast tenderness.

Hot flushes are less common with letrozole than clomid, whilst fatigue and dizziness are more common with letrozole.

Serious side effects are rare but can include visual disturbance (for example, blurry/double vision, floaters or flashes).

Ovarian hyperstimulation syndrome (OHSS) is a rare complication where the ovaries become enlarged. Symptoms may include:

• abdominal pain
• bloating
• nausea and vomiting.

If you’re concerned, stop the medication and contact the fertility clinic.

We don’t routinely recommend that you take either of these medications for more than 6 cycles. There has been studies that suggest a link between prolonged use of clomid and ovarian cancer, although later studies didn’t find an increase in risk (6).

References

1. National Institute for Health and Care Excellence (NICE). Fertility problems: assessment and treatment. Clinical guideline [CG156]. 2013. 
2. Royal College of Obstetricians and Gynaecologists. Diagnostic Laparoscopy. Consent Advice No. 2. 2017.
3. Wang R, Kim BV, Wely M van, Johnson NP, Costello MF, Zhang H, et al. Treatment strategies for women with WHO group II anovulation: systematic review and network meta-analysis. BMJ 2017; 356 :j138. doi:10.1136/bmj.j138
4. Franik S, Eltrop SM, Kremer JA, Kiesel L, Farquhar C. Aromatase inhibitors (letrozole) for subfertile women with polycystic ovary syndrome. Cochrane Database of Systematic Reviews. 2018 May 24;2018(5).
5. Teede H, Misso M, Costello M, Dokras A, Laven J, Piltonen T, et al. A new evidence-based guideline for assessment and management of polycystic ovary syndrome. Medical Journal of Australia. 2018 Oct;209(7):299–300.
6. The Practice Committee of the American Society for Reproductive Medicine. Use of clomiphene citrate in infertile women: a committee opinion. Fertility and Sterility]. 2013 Aug;100(2):341–8