Ovulatory Anomalies . As a woman ages, hormone levels may change, creating greater cycle irregularity and shorter cycles. Ovulation may not occur each month even though a woman is having regular menstrual periods. Luteal Phase Deficiencies . When the ovaries release an egg each month but do not produce enough of the hormone progesterone, this is called a luteal phase deficiency.
Progesterone is responsible for maintaining the lining of the uterus.
If progesterone production is insufficient, a fertilized egg will be unable to implant in the uterine wall. Because endometriosis has had more time to develop, it can be more severe and damaging in women over age 35. Egg Quality . As a woman ages, the quality of her eggs changes. Eggs from older women do not fertilize as well as those of younger women and are less likely to survive when they do fertilize.