Fertility & age: the impact of age

The impact of age on women

It’s an unfortunate fact that fertility declines with age. In general, the older you are, the lower your chances of conception.¹ Many couples learn about the impact of age too late. When they finally decide to seek help, advanced treatments may be their only option.

The most rapid decline in fertility potential has been found to occur from  age 35.² The decline seems linked to the number of healthy eggs in a woman's ovaries decreasing with age.¹

A woman is born with all the eggs she will ever have – about 400,000. During her reproductive years, only a single egg is likely to ripen each month. But over time, the supply is depleted and the remaining eggs become inactive. Poor egg quality leads to poor embryo quality. This in turn severely affects a woman’s chances of conception and carrying the pregnancy to term.

The exceptions

Everyone has heard about a career woman who holds off motherhood until her forties and then gives birth to twins – naturally. A woman can be 43 with good-quality eggs and still be fertile. She can also be 25 with poor quality eggs and be infertile. Both examples are extremely rare.

The point is that egg quantity and quality tends to decline significantly from your mid- to late 30s. It declines even faster in your early 40s. With this in mind, egg quantity and quality in an individual woman can be average for her age, better than average, or worse than average.

Other age-related factors affecting older women

• Irregular ovulation and changes to the quality of the uterine lining as hormone levels fluctuate over time
• Longer exposure to diseases such as endometriosis and uterine fibroids which affect the reproductive system¹
• A greater risk of miscarriage (spontaneous abortion) and genetic abnormalities¹

The impact of age on men

Age has less of an affect on male fertility. In part, this is because a woman is born with her egg supply complete, whereas sperm are constantly replenished after puberty. That said, the sperm of older men often loses some of its fertilizing potency. Sperm may become less motile and its shape may change.¹ For some men, advancing age is also associated with declining testosterone levels¹, decreased sexual interest and reduced sexual activity.

And now the good news

Whatever the cause, coping with fertility issues is never easy. But scientific advances over the past three decades have helped millions of men and women overcome problems.

If you or your partner have concerns, it’s best to act sooner rather than later. Depending on the underlying cause, many relatively simple procedures are available.

Before making a medical appointment, discuss your fertility plan as a couple and agree on what action to take.

^{1. Age and Fertility. A Guide for Patients. ASRM 2003; http://www.asrm.org/Patients/patientbooklets/agefertility.pdf  2. Practice Committee Report. Aging and infertility in women: a committee opinion. Fertil Steril 2002;78:215-219.  3. Definitions of fertility and recurrent pregnancy loss. Fertil Steril 2008;90:S60.}