How Conception Works
Natural conception requires ovulation of a healthy egg, sperm capable of fertilizing that egg, an open path through the fallopian tubes, and a receptive uterine environment for implantation. A disruption at any step can reduce fertility.
Common Contributing Factors
- Age — egg quantity and quality decline with age, most notably after the mid-30s.
- Ovulatory disorders — including PCOS and thyroid dysfunction.
- Tubal or uterine factors — from prior infection, endometriosis, fibroids, or surgery.
- Male factor — sperm count, motility, morphology, and DNA integrity.
- Unexplained — a meaningful share of cases show no single identifiable cause on standard testing.
When Evaluation Is Reasonable
Evaluation is commonly recommended after 12 months of trying, or 6 months if the female partner is 35 or older, and sooner when clinical circumstances warrant. See our signs to consider evaluation page.
What Evaluation Answers
Evaluation identifies likely contributing factors, quantifies ovarian reserve, characterizes sperm function, and confirms the anatomical picture. It informs — but does not determine — whether treatment is appropriate.