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Facts on fertility

Sometimes when a woman decides that the time is right to have a baby, she may be surprised to find it more difficult to fall pregnant than expected. Regardless of your stage of life, if you are considering having a baby, it is a good idea to talk your GP to discuss factors affecting fertility and how to help increase your chances of conceiving successfully.

Understand your ‘fertile window’ 

Your ‘fertile window’ is the time during a month when sperm in the fallopian tubes is most likely to meet an egg released from the ovary. This is usually from about two to three days before ovulation to when the egg has travelled down to the uterus. Having sex without using contraception at this time may increase your chances of conceiving.

Use our Ovulation Calculator to help you find out your ‘fertility window’.

What are some of the factors that may make it hard to fall pregnant? 

If you are a young and fertile couple in your 20s, you have a 25 percent chance of conceiving by having sex around the time of ovulation every month (when a woman's eggs are released, usually around the middle of the menstrual cycle). That's about a 90 percent chance of falling pregnant within a year. The odds are a bit lower if the timing of sex is random and not aimed at ovulation.

From her mid-30s, a woman's odds of conceiving decreases each year. Advancing age means fewer viable eggs are released and the chances of miscarriage increase. Men can also become less fertile as they age.

A couple isn't thought to have fertility problems until they've tried but failed to conceive for one year, although it is reasonable to seek help after six months of trying if you're already over 35. Around 40 percent of cases are due to the woman's infertility, and 40 percent are due to the man's infertility. For the remaining 20 percent of infertility cases, the cause is unknown.

Common factors that can affect fertility include:

  • lifestyle – poor nutrition, alcohol, drug or tobacco use, stress and anxiety, being overweight or obese
  • diabetes
  • pelvic infection, usually caused by sexually transmitted diseases
  • low sperm count or poor motility of sperm
  • blockage preventing sperm reaching the penis
  • fibroids in the uterus
  • endometriosis
  • polycystic ovary syndrome (PCOS).

Endometriosis and fertility 

Endometriosis is the growth of uterine tissue outside the uterus—usually on the ovaries and other pelvic organs and tissue. One of the symptoms of endometriosis is lower abdominal pain that often starts a day before a woman's period and lasts for two to three days. As many women consider lower abdominal or pelvic pain to be an unwelcome but 'normal' part of their menstrual cycle, they may not seek help for their symptoms for many years.

Not all women with endometriosis will be infertile—only about one third are affected. Endometriosis can cause scarring (adhesions) on the ovaries and fallopian tubes, causing blockage, and may affect egg release, fertilisation or the journey to implant in the uterus after fertilisation.

Watch our video on how endometriosis affects a woman's fertility, common symptoms, and how it can be treated to help achieve a pregnancy.

Find out more information about endometriosis.

Polycystic ovary syndrome (PCOS) and fertility 

PCOS is a hormonal disorder affecting about 10 percent of all women of reproductive age. The cause is unknown but it runs in families. Women with PCOS produce excessive amounts of androgens—male hormones like testosterone—in their ovaries. The ovaries may become dotted with tiny eggs that have failed to mature. Women with PCOS also have insulin resistance, which causes overproduction of testosterone as well as making them prone to diabetes and excessive weight gain.

Symptoms of PCOS can include:

  • irregular, infrequent and/or heavy periods
  • excessive facial or body hair
  • acne
  • tendency to gain weight around the abdomen.

Irregular and infrequent periods can mean a woman with PCOS may not ovulate each menstrual cycle which can contribute to their difficulty falling pregnant. In some cases, women with PCOS can achieve regular ovulation, and in turn improve their fertility, by making lifestyle and dietary changes to losing weight (around a five percent reduction in body mass).

Treatment with medication is usually not considered until after a three-to-six-month trial of lifestyle changes. This may involve medicines that help stimulate ovulation, either taken on its own or in combination with other treatments. These medications require a prescription from your doctor.

For some women with PCOS, assisted reproductive technology like in vitro fertilization (IVF) may be necessary to manage their infertility.

Find out more information with our Polycystic ovary syndrome (PCOS) video

Diagnosing and treating infertility 

Watch our video on common causes of infertility, how it can be diagnosed and treated and when to seek help from a Fertility Specialist.

Find out more information about infertility and in vitro fertilisation (IVF).

Further information 

Polycystic Ovary Syndrome Association of Australia

The Jean Hailes Foundation: Endometriosis

AccessA - Australia's national infertility network

Fertility Society of Australia


  1. IVF Australia. [online] Available from:
  2. Jean Hailes for Women’s Health. Endometriosis. [online] [Last updated Jan 2012, accessed Mar 2014] Available from:
  3. Polycystic Ovary Syndrome Association of Australia. What is PCOS? [online] Available from:
  4. Virtual Medical Centre. Infertility. [online] 2008 [Last updated Oct 2010, accessed Mar 2014] Available from:

Last updated: 31 March 2014

This information has been developed and reviewed for Bupa by health professionals. To the best of their knowledge it is current and based on reputable sources of medical research. It should be used as a guide only and should not be relied upon as a substitute for professional medical or other health professional advice.

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The videos on this health page have been produced by and used with permission of IVFAustralia and Melbourne IVF.