Impact of Age and Ovarian Reserve On Pregnancy
Women today are healthier and taking better care of themselves than ever before, but improved health later in life does not offset the natural age-related decline in fertility. As age increases, a women’s ovarian reserve decreases. Resulting in reduced egg quantity, declined egg quality, and higher chances of abnormalities in their chromosomes (genetic material). All these factors together mean that older women have lower pregnancy rates and higher miscarriage rates.
The Age Factor
The ability to have a baby decreases in all women as they get older, but the exact age when a woman can no longer conceive varies. About one third of couples will have problems getting pregnant when the female partner is age 35 or older (ASRM). The chart below shows fertility declines significantly for a woman in her mid-30s and accelerates into her late 30s.
There are several tests that can help show a woman’s fertility potential, also called ovarian reserve (ASRM). Physicians generally start with blood tests to evaluate hormone levels. The goal is to predict the status of a woman’s ovarian reserve, which tells the physician roughly how many eggs are remaining and gives an idea of how the woman’s fertility compares to other similarly aged women.
Common tests include follicle-stimulating hormone (FSH), estradiol and anti-müllerian hormone (AMH). FSH and estradiol are checked at the beginning of the menstrual cycle, usually done on cycle day 3, but can be drawn from day 1 to 5. These hormone levels show important information about how the ovaries and pituitary gland are working together. Usually FSH levels are the lowest in the beginning of the cycle and then increase causing follicle growth and allowing the egg to mature. If the FSH is too high, the egg does not mature properly which presents a less likely chance for pregnancy.
AMH is the best test available for ovarian reserve and can be drawn at any time during the menstrual cycle. It is produced in the follicle and is related to the number of eggs remaining. The higher the number of eggs in the ovaries, the higher level of AMH in the bloodstream. A typical AMH level for a fertile woman is 1.0–4.0 ng/ml and AMH level under 1.0 ng/ml is considered low.
It’s important to remember that no single test is conclusive of a woman’s ovarian reserve, but rather a comprehensive picture obtained by factoring in the woman’s age and appropriate testing.
When to see a Reproductive Endocrinologist
Infertility is usually diagnosed if no conception after one year of unprotected intercourse. If you are 35 or older however, you should initiate your evaluation after 6 months of unprotected intercourse. If you are concerned about fertility or have an obvious medical problem affecting your ability to conceive, such as irregular menstrual cycles (suggesting that you are not ovulating), diagnosed polycystic ovarian syndrome, sexual dysfunction, a history of pelvic disease, prior surgery, or, if your partner has a known fertility problem, you should begin the infertility evaluation immediately. At Brown Fertility, we welcome the opportunity to help grow your family.