Metformin, clomifene, letrozole and fertility treatment for PCOS
Originally written by Zita West. Updated by femme to reflect current evidence-based PCOS fertility guidance.
PCOS can make conception more difficult when ovulation is infrequent or absent. The good news is that there are established fertility treatments, and the right option depends on whether ovulation is the main problem and on the rest of the fertility assessment.
Why can PCOS affect fertility?
PCOS is associated with ovulatory dysfunction and higher androgen levels. Some people with PCOS also have insulin resistance. These features can make ovulation less regular, but PCOS does not mean pregnancy is impossible.
Medicines used for ovulation induction
Letrozole
The 2023 International Evidence-based PCOS Guideline recommends letrozole as the preferred first-line medicine for anovulatory infertility in PCOS when there are no other infertility factors.
Clomifene
Clomifene can stimulate ovulation and remains an established fertility medicine. Depending on the situation, it may be used alone or with metformin.
Metformin
Metformin improves insulin sensitivity and is used for metabolic features of PCOS. It can also have a role in fertility treatment, although it is not simply an “egg quality” medicine and may be less effective for ovulation induction than letrozole.
Second- and third-line treatment
Gonadotrophins, ovarian surgery in selected cases and IVF can be considered when first-line ovulation treatment is unsuccessful or when another fertility factor makes assisted conception appropriate.
Lifestyle can support health, not replace fertility treatment
A balanced diet, regular activity, sleep and weight management where relevant can support metabolic and reproductive health. The PCOS guideline emphasises healthy lifestyle for everybody with PCOS, including people who are not overweight.
There is no single low-GI diet or exercise routine that guarantees ovulation or pregnancy, and fertility difficulties should not be blamed on somebody's lifestyle.
What about supplements?
Inositol is widely marketed for PCOS. Current international guidance says it may be considered, but clinical benefits are limited and specific types or doses cannot be confidently recommended from the available evidence.
Omega-3 and vitamin D have roles in general nutrition, but supplements should not be presented as proven fertility treatments for PCOS unless a deficiency or specific clinical indication has been identified.
Age and PCOS
PCOS does not remove the age-related decline in fertility. Treatment can help address ovulation problems, but no combination of medicines, supplements or lifestyle changes can reverse reproductive ageing.
If you are struggling to conceive, a fertility assessment can look at ovulation, sperm, tubal factors and other causes rather than assuming PCOS explains everything.
The bottom line
For PCOS-related anovulatory infertility, evidence-based treatment starts with identifying the cause and choosing the right ovulation-induction strategy. Letrozole is now the preferred first-line medicine in the international guideline, while clomifene and metformin still have important roles in selected patients.
Further information
2023 International Evidence-based PCOS Guideline
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