1. Ovulation Disorders: Conditions such as polycystic ovary syndrome (PCOS) can disrupt regular ovulation, leading to infertility.

2. Tubal Factors: Blocked or damaged fallopian tubes can prevent the egg from being fertilized or reaching the uterus, causing infertility.

3. Endometriosis: Endometriosis, a condition where tissue similar to the uterine lining grows outside the uterus, can affect fertility by causing inflammation and scarring.

4. Uterine Issues: Abnormalities in the uterus, such as fibroids or polyps, can interfere with implantation or cause miscarriages.

5. Age-related Factors: As women age, the quantity and quality of their eggs decline, making conception more difficult.

6. Pelvic Inflammatory Disease (PID): Infections such as sexually transmitted infections (STIs) can cause scarring and damage to the reproductive organs, leading to infertility.

7. Unexplained Infertility: In some cases, despite thorough testing, the cause of infertility remains unexplained.