What are the main causes of infertility in couples?

When a couple consults me for this reason, I always start with a simple question: how long have you been trying without success? The answer guides my investigation.

A period of 12 months without pregnancy is the threshold used to define infertility in women under 35. Beyond that age, this period shortens to 6 months.

Female factors: age, ovulation, and pathologies

A woman’s age remains the primary factor for infertility in couples. A study published in *Fertility and Sterility* (2018.

1,232 patients) reports a monthly fertility rate dropping from 25% at age 30 to only 5% after age 40. I see too many patients downplaying this parameter. Yet, oocytes age well before the rest of the body.

Ovulation disorders affect 25% of female infertility cases. Polycystic ovary syndrome (PCOS) is the leading cause.

A 28-year-old patient came to see me after two years of unsuccessful attempts. Her irregular cycles and elevated LH levels confirmed the diagnosis.

Some oculoplastic surgeons favor ovulation induction as first-line treatment. I prefer to start with metabolic management: targeted weight loss and metformin. Why? Because 60% of women with PCOS regain ovulatory cycles with this approach alone.

Endometriosis complicates 30 to 50% of couple infertility cases. This condition does more than cause pain. It impairs oocyte quality and creates a hostile uterine environment.

A Japanese study (2020, 456 women) showed that patients with endometriosis had 40% lower chances of conceiving naturally.

Some gynecologists recommend systematic surgery. I reserve this for severe cases with tubal obstruction. In other situations, I favor ovarian stimulation combined with intrauterine insemination.