Delaying pregnancy is a common choice for women in today’s society. The number of women in their late 30s and 40s attempting pregnancy and having babies has increased in recent years. This is due to a number of factors, such as delaying childbirth until careers are established, waiting for a stable relationship, wanting to achieve financial security, or being unsure about the desire for parenthood. Also, information in the media about assisted reproductive technologies may give women an unrealistic sense of security that childbearing can be delayed. It is important that women realise that age may affect their ability to conceive and have a healthy pregnancy. 


Females are born with all their eggs, different to the male who produces sperm on an ongoing basis throughout his life. Every month, once a female has reached puberty, many eggs start the maturation pathway during the early days of the cycle.  However most of her developing eggs are lost within the ovary, only the dominant egg within a cyst like structure called a follicle continues to full maturity and ovulation. The majority of eggs produced are not always genetically viable hence a pregnancy is not guaranteed in each cycle. Due to an ongoing deterioration of the eggs the pregnancy rate drops rapidly after a woman has reached her mid-thirties. Fertility clearly declines with advancing age, especially after the mid-30s, and women who conceive are at greater risk of pregnancy complications. As the ovarian follicular pool decreases, women will experience infertility, sterility, cycle shortening, menstrual irregularity, and finally menopause. 

Women enter the peri-menopausal stage (the stage before menopause) at varying ages – from early thirties to late forties. This peri-menopausal stage indicates that a woman is starting to run out of eggs. Generally the eggs she is producing at this stage are poor in quality. Maternal age is a factor that refers to the deterioration of the ovarian function and not her physical age.


There is a change in the hormonal cycle, it shortens, lengthens or becomes irregular.

The FSH (Follicular Stimulating Hormone) level starts rising slowly there is also a rapid estrogen rise at the commencement of the cycle.

Irritability and tiredness are also symptoms.


FSH and estrogen blood levels should be tested on day two or day three of the menstrual cycle. The FSH level does fluctuate during the peri-menopausal stage, therefore it should be repeated.


Older patients seeking pregnancy as well as patients experiencing infertility beyond the age of 35 should seek early basic evaluation with assessment of ovarian reserve, ovulatory status, uterine and tubal anatomy, and semen parameters. In general, infertility examination is deferred until after at least one year of unprotected intercourse; however, in the older age group, it is appropriate to initiate this evaluation after as few as 6 months of attempted conception due to the rapid decline of treatment success over time. Therefore, abnormalities if present may be addressed as soon as possible, when such intervention would still allow a reasonable chance of pregnancy. Similarly, trials of infertility treatment should be concerted with fairly rapid progression to more advanced infertility treatments when indicated. It should be cautioned that normal testing for ovarian reserve (such as day 2/3 FSH) do not negate the effects of chronologic age on oocyte quality, embryo implantation, and pregnancy rates.

Treatment of age-related infertility is somewhat limited, with no specific treatment available for oocyte abnormalities or decreased ovarian reserve. In general, treatments for normal older women is directed toward increasing the number of available oocytes through controlled ovarian hyperstimulation and/or assisted reproductive technologies. However, due to the low implantation rates, these treatments are associated with a disappointing success rates beyond the age of 40. Delivery rates per attempted cycle of in vitro fertilisation are less than 5% by the age of 43 in spite of improvements in implantation through modifications such as assisted hatching. On the other hand, excellent success rates can be achieved through oocyte donation in women up to and beyond the age of 50 years.

There is no treatment to prevent the onset of the menopausal phase. Utilising donor eggs or adoption may be the only options available.

Fertility Statistics

Statistics of women trying to get pregnant, without using fertility drugs or in vitro fertilisation:

  • At age 30 
    • 75% will have a conception ending in a live birth within one year
    • 91% will have a conception ending in a live birth within four years
  • At age 35 
    • 66% will have a conception ending in a live birth within one year
    • 84% will have a conception ending in a live birth within four years
  • At age 40 
    • 44% will have a conception ending in a live birth within one year
    • 64% will have a conception ending in a live birth within four years

Risk of birth defects

A woman’s risk of having a baby with chromosomal abnormalities increases with her age. Down syndrome is the most common chromosomal birth defect, and a woman’s risk of having a baby with Down syndrome is:

  • At age 20, 1 in 1,440
  • At age 25, 1 in 1,380
  • At age 30, 1 in 960
  • At age 35, 1 in 340
  • At age 40, 1 in 84
  • At age 45, 1 in 38
  • At age 50, 1 in 44
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