How Fertility Changes With Age: What Women and Men Should Know

Women and age

People are born with all the eggs they will ever have, about one to two million at birth, and the number falls steadily to a few hundred thousand by puberty and far fewer by the mid-30s. Equally important, the proportion of eggs with a normal number of chromosomes falls with age, which is why miscarriage risk rises and why the chance of conceiving each month declines.

ACOG notes that a healthy woman at 30 has about a 20 percent chance of becoming pregnant each month, and that by 40 the chance is under 5 percent. These are averages, and many people conceive naturally in their late 30s and 40s while others in their 20s need help.

What changes

• From about 30: a gradual decline in the monthly chance of pregnancy
• After about 35: a more rapid decline in egg quantity and quality, and a higher miscarriage risk
• By 40 and beyond: a much lower monthly chance and a higher need for treatment such as IVF, sometimes with donor eggs

Men and age

Male fertility declines more gradually and less predictably. Studies link older paternal age with lower sperm quality and a longer time to conceive, and with some increased risks to pregnancy and children. Lifestyle factors matter too. See partner health and male factor infertility.

What does not change the clock

No diet, supplement or exercise plan restores egg quality or number. Healthy habits are worth keeping for general health and pregnancy outcomes, but be wary of claims about “reversing ovarian aging.” See low ovarian reserve.

What you can do

• Do not wait if you are 35 or older. See when to see a fertility specialist.
• Test both partners and review options early.
• Consider egg freezing if you may want children later and are not ready now.
• Know your treatment options: ovulation induction, IUI, IVF and donor eggs.
• Look after your health with nutrition, sleep and not smoking.

A note on “advanced maternal age”

Clinicians often use the term for pregnancy at 35 or older. It describes statistics, not individuals, and many pregnancies at these ages are healthy. Early prenatal care helps.

Age 20s and early 30s

Fertility is generally at its highest in the 20s, and starts to ease gradually by the early 30s. Most healthy couples in this age range conceive within a year of trying. If it does not happen, causes are more likely to relate to specific conditions, such as PCOS, endometriosis, tubal problems or male factor, than to age alone. That is why evaluation after 12 months, or earlier with risk factors, remains important.

Mid to late 30s

After about 35, the decline accelerates, and the proportion of eggs with a normal number of chromosomes falls. The chance of conceiving each month is lower, and the risk of miscarriage is higher. This does not mean it is impossible: many people conceive naturally in their late 30s. It does mean that waiting costs more, and that evaluation after six months is advised. Many people at this stage choose to move to IVF sooner when other treatments do not work.

40 and beyond

By 40, natural conception rates are low per cycle, and the chance of success with a person’s own eggs declines, even with IVF. Donor eggs often give higher success rates. Some people conceive naturally in their early 40s, but expectations should be realistic. It is reasonable to consider seeing a specialist promptly and to discuss all options, including donor eggs, without delay.

What about the partner’s age?

Sperm production continues throughout life, but semen quality can decline with age, and paternal age is associated with a longer time to conception. There is also a slight association between older paternal age and some risks to children. Compared with the female age effect, the male one is smaller and less predictable.

Pregnancy health at older ages

Pregnancy at 35 and older is common and often healthy, but risks such as gestational diabetes, high blood pressure and chromosomal conditions are more common. Early prenatal care, screening options and good health habits help. Discuss genetic screening and diagnostic testing with your clinician.

Planning with age in mind

• Know your timeline. Use the timing check to plan an evaluation.
• Test both partners early.
• Consider preserving fertility if you are not ready to conceive. See egg freezing.
• Ask about treatment sooner if you are over 35.
• Look after your health, with sleep, nutrition and not smoking.

Avoiding fear and shame

Age statistics can sound harsh, and many people feel guilty for not starting earlier. Life rarely follows a perfect timeline, and your choices were made with the information and circumstances you had. Focus on what you can do now.

Emotional impact

Feeling pressure about time is common and can be hard. Reach out for support if you need it. See stress and emotional health.