How & Why Does Age Affect Fertility

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There are plenty of stories of women and couples having a baby in their late 30s or early 40s, but it’s a biological fact that fertility declines as both women and men age. There are plenty of reasons to put off having children—career, finances, travel, and simply not feeling ready just yet—but having a baby later in life can be met with difficulty and some complications, simply because of age.

However, at Arizona Center for Reproductive Endocrinology & Infertility, it’s our goal to help any individual or couple have a baby, no matter their age. Here’s what we hope you’d understand about age and fertility.

Peak Fertility
A woman’s peak fertile years are during her late teens into her 20s. A woman is born with all the eggs she will ever have, so as she ages, the number (and quality) of eggs will reduce over time; this is why fertility decreases over time.

As for men, semen quantity typically peaks between the ages of 30 and 35, with a distinct decline in the 40s.

For healthy couples in their 20s and early 30s, approximately one in four women will get pregnant during a single menstrual cycle.

Fertility Decline in Women
By age 30, fertility for women starts to decline. The decline becomes more rapid in their mid-30s, and by age 45, fertility has declined so much that getting pregnant naturally—without any assisted reproductive procedures—is unlikely to happen. As they age, women are at a higher risk for disorders that can affect their fertility as well, such as endometriosis and uterine fibroids.

In fact, by age 40, only around 1 in 10 women will get pregnant per menstrual cycle.

Older age comes with other challenges aside from just achieving a pregnancy. The remaining eggs an older woman has in her ovaries are more likely to have chromosomal abnormalities. Down syndrome is the most common chromosomal disorder that occurs with late pregnancy. When a woman gets pregnant in her 20s, the risk is 1 in 1,480, but as she reaches 45 years of age, the risk increases dramatically to 1 in 35.

Preimplantation genetic screening (PGS) is available so that an older couple, or woman, can assess the risk that a baby will be born with a birth defect or genetic disorder. At AZCREI, we will review the testing options available to you to help you an informed choice on the best way to move forward with infertility treatments.

In addition to PGS, we can also conduct tests to determine the number and quality of your ovarian reserve. These blood tests look at follicle-stimulating hormone (FSH) or antimüllerian hormone (AMH) levels to assess potential fertility. An ultrasound may sometimes be used to count the number of follicles (antral follicle count, or AFC) as well. However, it is important to note that there is no single test that will perfectly measures a woman’s ovarian reserve or fertility.

Despite the challenges, many women older than 35 years can have successful pregnancies and healthy babies. While you can’t preserve fertility, you can take measures to increase the chances of pregnancy when you’re older, such as freezing your eggs while in your 20s, especially if you’re considering putting off pregnancy until later in life.

Age, Fertility, Men
For the most part, age has less of an effect on men’s fertility, but younger men do have more active and better-quality sperm than older men.

Barring any health issues, men typically produce millions of new sperm every day, but men older than 40 have fewer healthy sperm, than men at a younger age. Semen and sperm motility also decrease between the ages of 20 and 80.

A semen analysis, can help determine the number, shape, and movement of a man’s sperm to help estimate his potential fertility.

Don’t Give Up Hope
Age does make it more difficult to get pregnant, but it’s not impossible. There are several medical strategies and infertility treatments that may increase your chance of conceiving. If age has become a factor in your ability to get pregnant, schedule an appointment with AZCREI today by contacting us online or calling 520-326-0001.


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