What are the most common causes of infertility in women?

Best Answer

The most common causes of infertility in women fall into five main categories: ovulation disorders (including PCOS and thyroid issues), fallopian tube damage or blockage, endometriosis, uterine or cervical abnormalities, and age-related decline in egg quality and quantity. These are well-supported by major reproductive medicine organizations like the WHO and ASRM. Importantly, about 15–30% of cases are classified as "unexplained infertility," meaning standard tests don't reveal a clear cause — but this doesn't mean treatment can't help. It's also worth knowing that in roughly 15% of couples, male-factor infertility plays a role, so a partner evaluation can be equally important. If you're under 35 and have been trying to conceive for 12 months without success — or 6 months if you're 35 or older — it's a good time to speak with an OB-GYN or fertility specialist. If you already have symptoms like irregular periods, significant pelvic pain, or a history of endometriosis or STIs, don't wait for those timeframes; seek evaluation sooner.

Where the AIs Agree

• Ovulation disorders (especially PCOS) are among the most common causes, affecting roughly 20–40% of women with infertility.
• Fallopian tube damage or blockage — often caused by pelvic inflammatory disease, endometriosis, or prior surgery — is another leading cause.
• Endometriosis is a significant and frequently cited contributor, affecting approximately 10–15% of cases.
• Uterine or cervical abnormalities (fibroids, polyps, structural issues) can interfere with implantation or conception.
• Age is a well-established factor, with fertility declining notably after 35 and more sharply after 40.
• All responses agree that professional medical consultation is appropriate after 12 months of trying (or 6 months for women 35+).

Where the AIs Disagree

• Response 3 (Claude) explicitly flagged male-factor infertility as a consideration (~15% of couples), which only one other response briefly touched on — this is a clinically important point the others largely omitted.
• Responses varied in how much weight they gave to lifestyle factors (obesity, smoking, caffeine). ChatGPT discussed them in detail; Claude and Grok treated them more briefly; Gemini's response was incomplete and offered no usable detail on this point.
• Grok cited specific percentage ranges and named sources (WHO, ASRM, NEJM), lending more apparent precision, while other responses gave broader estimates — the actual data ranges are close, but the confidence framing differs.
• The range given for "unexplained infertility" varied: Claude cited 15–20%, Grok cited 10–30%, reflecting genuine variability in the literature rather than a clear consensus figure.
• ChatGPT mentioned environmental toxins and emotional stress as possible but unestablished factors; other responses did not raise these, which is a meaningful difference in scope.