Among women, the most common causes of infertility include problems with ovulation, damage to the fallopian tubes or uterus, or problems with the cervix. Age can contribute to infertility because as a woman ages, her fertility naturally tends to decrease: her ovaries become less able to release eggs, she has fewer eggs left, her eggs are not as healthy, she is more likely to have health conditions that can cause fertility problems, and she is more likely to have a miscarriage. Smoking or excessive alcohol use, or experiencing extreme weight gain/loss or excessive physical or emotional stress also contribute to this condition.