There are many contributing factors to why Fertility declines once a Woman is 40 and above, such as, increased room for genetic errors, decreased reserve of healthy follicles in the ovary, and increased oxidative stress in the ovary. However, a part of this process of declining fertility is related to a shorter follicular phase (the early part of the cycle where the follicle in the ovary matures).
A common trend for Women above 40 is a pattern of irregular menstrual, however, hidden in those cycles is usually a shorter follicular phase. This is because levels of FSH (follicle stimulating hormone) tend to be higher after 40 as the brain tries to push the ovary to continue maturing more follicles. The high levels of FSH will then accelerate the follicular phase, so instead of lasting about 10-12 days (occurring in younger women) it will only last 7-10 days.
A second cause for an accelerated follicular phase is that a portion of the Women above 40 will have a second surge of Estrogen in the second half of the previous cycle (estrogen should typically only be high in the first half of the cycle). This second spontaneous surge of estrogen can stimulate a second follicle which will then be released earlier in the next cycle.
An accelerated follicular phase can decrease the quality of the egg, and an egg of poor quality is associated with decreased fertility as it is much more fragile and is more likely to have errors in its genetic content.
For Women above the age of 40 trying to conceive, a helpful addition to a much larger treatment plan is treatment to try and return the follicular phase to normal length (10-12 days)to allow the follicle to undergo full development.
This article is in no way a replacement for medical advice or medical care, it is advised that anyone concerned about their Reproductive Health should speak with their Naturopathic Doctor or Primary Care Provider.