Impact of age on fertility

As a society, we are waiting longer to pursue parenthood. That makes us feel like there is plenty of time to put off having children. However, the reality of our bodies is a different story.

The most important factor that determines a woman’s ability to have a healthy pregnancy is her age. Women are born with all of the eggs they will have in life, and in the early reproductive years, eggs decline in both quantity and quality.

As women enter their mid-30’s the decline accelerates rapidly. Women may still be ovulating, but lower quality eggs are less likely to fertilize and develop into a healthy pregnancy. The decline in egg quality also explains why there are increasing rates of miscarriages and chromosomal abnormalities, such as Down syndrome, in the mid-30’s and beyond. Unfortunately, nothing can be done to slow down or reverse the decline in egg supply over time.

Tests are available to measure a woman’s ovarian reserve, or remaining egg supply, through blood work or ultrasound. At Carolina Conceptions we primarily use the AMH test (Antimullerian Hormone), which is a simple blood test that can be done on any day of the cycle. Another commonly used blood test is the cycle day 3 test for FSH (follicle stimulating hormone) and estradiol. While women are going through treatment, we also use ultrasound to count the number of antral follicles present within the ovary, which is a representation of the number of small, immature eggs that are available during the next month.

None of these tests are 100% accurate in assessing ovarian reserve, and it is important to distinguish that ovarian reserve testing does not reliably predict fertility or the ability to become pregnant.

Some women have very poor ovarian reserve but are fertile, while some who have excellent reserve are infertile. Due to the decline in ovarian reserve with age, for women > 35 an evaluation should begin after 6 months of trying to conceive.

Other factors to consider with increasing age is the possibility that gynecological problems develop over time. The chances of developing problems with the female anatomy are higher as women age. For example, uterine fibroids and endometriosis are conditions that may not be significant at early stages, but later stages are more likely to affect the ability to become pregnant and stay pregnant. Furthermore, women who are pregnant later in life are more likely to develop complications of pregnancy, such as gestational diabetes and preeclampsia (high blood pressure).

By the time a woman reaches 40, her chances of conceiving naturally or via IVF with her own eggs, is very slim. Women at ages 40+ can still get pregnant, but their chances are increased (by as much as 70%!) using IVF with donor eggs.