PCOS and Fertility: Causes, Impact on Conception & Treatment Options

> A note on the name: In May 2026, polycystic ovary syndrome (PCOS) was formally renamed polyendocrine metabolic ovarian syndrome (PMOS) following a global consensus process. The old name was inaccurate — the condition affects multiple hormone and metabolic systems, not just the ovaries, and "polycystic" wrongly implies ovarian cysts. Nothing about the condition, its diagnosis or its treatment has changed. Both names will be used side by side for the next few years. We use PCOS below since that is the term most people know.

PCOS and fertility

The good news first

PCOS is among the more treatable causes of difficulty conceiving. The underlying problem is usually irregular or absent ovulation rather than an inability to conceive. Restore ovulation, and natural conception often follows.

Women with PCOS also frequently retain good ovarian reserve, which works in your favour over time.

First-line treatment

Letrozole should be the first-line pharmacological treatment for ovulation induction in women with PCOS and anovulatory infertility who have no other infertility factors. This is an evidence-based recommendation in the International Guideline.

Letrozole is preferred over clomiphene citrate specifically because it improves ovulation, clinical pregnancy and live birth rates — not just a surrogate measure.

Two practical points:

• Letrozole remains off-label in many countries. Where its use is not permitted, other agents may be used. Check the position where you are treated.
• There is no evidence of increased teratogenicity with letrozole compared with other ovulation induction agents. This is the concern most often raised against it, and it is not evidence-based.

Where clomiphene fits

Clomiphene could be used in preference to metformin. But note the multiple pregnancy risk is increased with clomiphene, so cycles may require ultrasound monitoring — a real cost of choosing it that is often left out of the comparison.

Where metformin fits

Metformin could be used alone to improve clinical pregnancy and live birth rates — whilst informing women that there are more effective ovulation agents. That clause is part of the recommendation itself.

There is a genuine reason to choose it anyway: the guideline notes that healthcare and resource burden — monitoring, travel and costs — is lower with metformin. For someone facing distance or cost barriers, that is a named and legitimate consideration.

Age and screening for other fertility factors should be discussed before prescribing it.

Weight

Where BMI is raised, 5 to 10% weight loss can restore ovulation without medication. That is a smaller change than most people expect.

Two things worth saying plainly: weight loss is physiologically harder in PCOS — insulin resistance with compensatory high insulin is present in 85% of those affected — and PCOS occurs in lean women too, for whom weight loss is not the answer.

Before starting treatment

These recommendations assume a completed fertility assessment of both partners. Screening for other factors first is a prerequisite, not an optional step.