• Age affects the fertility of both men and women.
  • Age is the single biggest factor affecting a woman’s chance to conceive and have a healthy baby.
  • A woman’s fertility starts to decline in her early 30s, with the decline speeding up after 35.
  • Male fertility decline is more subtle, but a man’s age affect the chances of his (female) partner conceiving, and increases the risk of miscarriage, and the child’s risk of mental health and developmental disorders.
Age affects the ability to conceive and have a healthy baby. Age is the single biggest factor affecting a woman’s fertility. For men, age-related fertility decline is more subtle but does happen.

Women’s age and fertility

A woman is born with all the eggs she is going to have in her lifetime. Her eggs age with her, decreasing in quality and quantity. This is why age is the single most important factor affecting a woman’s fertility. While good health improves the chance of getting pregnant and having a healthy baby, it does not override the effects of age on a woman’s fertility.

In her early to mid-20s, a woman has a 25 to 30 per cent chance of getting pregnant every month. Female fertility generally starts to decline when a woman is in her early 30s, and the decline speeds up after the age of 35. By age 40, the chance of getting pregnant in any monthly cycle is down to around five per cent.

It is a common misconception that IVF treatment can overcome age-related infertility. A woman’s age also affects the chance of success with IVF. The chance of a live birth resulting from one IVF cycle for women of different ages in 2014 in Australia and New Zealand is illustrated.

age and fertility

For older women the chance of having a baby increases if they use eggs donated by a younger woman. 

The risk of pregnancy complications increases with age too. The risk of miscarriage and chromosomal abnormalities in the fetus increase significantly from age 35. Complications such as gestational diabetes, placenta previa (when the placenta covers all or part of the cervix, which increases the risk that the placenta will detach), caesarean section, and still birth are also more common among older than younger women.  

Men’s age and fertility

While the effects of female age on fertility have been known for a long time, more recent studies have found that the age of the male partner also affects the chance of pregnancy and pregnancy health. 

Male fertility generally starts to decline around age 40–45 years when sperm quality decreases. Increasing male age reduces the overall chances of pregnancy and increases time to pregnancy (the number of menstrual cycles it takes to become pregnant) and the risk of miscarriage and fetal death. 

Children of older fathers also have an increased risk of mental health problems (although this is still rare). Children of fathers aged 40 or over are five times more likely to develop an autism spectrum disorder than children of fathers aged 30 or less. They also have a slightly increased risk of developing schizophrenia and other mental health disorders later in life.

  • Harris I, Fronczak C, Roth L, Meacham R, 2011, ‘Fertility and the Aging Male’, Reviews in Urology, vol. 13, no. 4, pp. e184-e190. More information here.
  • McGrath J, Petersen L, Agerbo E, et al. 2014, ‘A comprehensive assessment of parental age and psychiatric disorders’, JAMA Psychiatry, vol. 4081, epub. More information here.
  • Schmidt L, Sobotka T, Bentzen JG, Nyboe Andersen A 2012, ‘Demographic and medical consequences of the postponement of parenthood’, Human Reproduction Update, vol. 18, no. 1, pp. 29–43. More information here.
  • Steiner AZ, Jukic AM 2016, ‘Impact of female age and nulligravidity on fecundity in an older reproductive age cohort’, Fertility and Sterility, vol. 105, no. 6, pp. 1584–1588. More information here.
  • Biro MA, Davey M-A, Carolan M, Kealy M 2012, ‘Advanced maternal age and obstetric morbidity for women giving birth in Victoria, Australia: A population based study’, The Australian and New Zealand Journal of Obstetrics and Gynaecology, vol. 52, no. 3, pp. 229–234. More information here.
  • Harris K, Fitzgerald O, Paul R, et al. 2016, Assisted reproductive technology in Australia and New Zealand 2014, National Perinatal Epidemiology and Statistics Unit, University of New South Wales, Sydney. More information here.

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Reproductive system - female

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Fertility, pregnancy and childbirth

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This page has been produced in consultation with and approved by: Victorian Assisted Reproductive Treatment Authority

Last updated: May 2017

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