How Age Affects Fertility

Growing up, forging an identity, and building a life in a world that’s increasingly complex and fast-moving was enough of a challenge. You didn’t want to complicate that early journey with children you weren’t emotionally and financially able to care for in the ways you knew they deserved.

But now you’re stable. You’re ready to expand your life by welcoming a new life into the world. Except, after more than a year of trying (if you’re under 35) or six months of trying (if you’re over 35), your OB/GYN gives you and your partner some unwelcome news: You’re officially considered infertile.

Dr. Vicken Sepilian, an infertility specialist and endocrinologist who serves the Greater Los Angeles area, knows how shocking hearing the word “infertile” can be. But one word isn’t the end of your story. Understanding why your fertility declines with age can help you find strategies to increase the odds that you’ll conceive a healthy baby in time.

A limited egg supply

As an infant girl welcomed into the world by your own mother, your ovaries were already stocked with all of the eggs you’ll ever produce. Most baby girls are born with about a million eggs. But as you grow up and age, the number of eggs (your ovarian reserve) declines.

By the time you’re in your 30s, your egg supply dwindles quickly. At age 37, you only have about 25,000 eggs left in reserve.

In your 20s and 30s, your ample supply of eggs means you have about a 25% chance of conceiving after trying to get pregnant for three months. The odds plummet to just 10% after age 35, and 7% at age 40. Dr. Sepilian determines your ovarian reserve with a simple blood test to help you determine your best options for conception.

In addition to the decrease in the number of eggs you have available for fertilization, the quality of your eggs also diminishes with age. You’re more likely to have a complicated pregnancy, or give birth to a child with chromosomal or genetic abnormalities, including Down syndrome. If you do become pregnant after age 35, your pregnancy is considered “high risk,” and you and your baby need additional tests and support to ensure a healthy pregnancy and delivery.

Hormones decrease or fluctuate

Around your 40s, you enter a stage called perimenopause, which is the period of life that precedes menopause (the end of your period and your fertility). Fluctuations in your hormones during perimenopause can cause irregularities in your menstrual cycle that make it difficult to determine when you’re most fertile -- which complicates conception.

Dr. Sepilian helps determine when you’re mostly likely to ovulate, and if you’re ovulating at all, with blood tests that measure key hormones such as luteinizing hormone, follicle-stimulating hormone, progesterone, and prolactin. If you’re not ovulating regularly, Dr. Sepilian may recommend ovulation induction therapies or medications that regulate your hormone levels.

Sperm count decreases with age, too

Although much of the focus on infertile couples is on the woman’s age, your partner’s age also affects conception odds. Men over the age of 40 have lower numbers of sperm, and their sperm may be less motile. Age reduces a man’s ability to conceive by about 11% per year.

And just as the quality of women’s eggs declines with age, so does the quality of sperm. Researchers found that about 50% of cases of Down syndrome were due to the sperm quality of older fathers. Men over 50 were three times as likely to father a child with schizophrenia.

Help is here

The good news is that the age at which women and men have healthy babies continues to increase. If you’re having trouble conceiving, Dr. Sepilian conducts a fertility evaluation for both you and your partner to identify any issues and to devise a custom-designed treatment plan, ranging from hormone therapy to in vitro fertilization.


To find out more about how to increase your chances of conceiving a child at any age, contact Dr. Sepilian for an evaluation. You can reach our office through the online form or by phoning one of our offices in Glendale or Santa Monica.

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