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To get pregnant it is necessary for a woman to have sex with a man around the time of the month when she is ovulating. The chance of getting pregnant can be affected by several factors related to both the man and the woman including: age, weight and whether either smoke or drink alcohol.
Fig 1. Proportion of women pregnant over 2 years
For a couple to be fertile, the woman needs to produce an egg from an ovary each month and her tubes must not have any blocks to the passage for the egg and sperm and the man would not have problems producing sperm.
If a couple is fertile and trying to have a baby, most women (up to 85%) will get pregnant within a year if they are having sex regularly and not using contraception. Up to 95% will get pregnant within two years. These are averages, some women will get pregnant quickly and some will take longer.
Infertility can be the result of problems with the woman (40%), the man (40%) or both (10%) and in the remaining 10% of the population the cause is unknown.
When a woman is born there are usually one million eggs in each of her two ovaries and these are the only eggs she will produce. Normally one egg will be released when she ovulates every month during her menstrual cycle. Approximately 400-500 eggs will be released over her lifetime. As a woman gets older the rest of the eggs disappear, break down or deteriorate and by the time she reaches menopause, there are no eggs left.
As a woman ages it takes longer to get pregnant, the chance of getting pregnant decreases and the quality or health of the eggs decreases too.
Women and their partners should ideally see a doctor for a check up if they are planning to have a baby. If a woman has been trying to get pregnant for more than a year, she should see a doctor. If she is over 35 years old, she should see a doctor if she has been trying for six months or more and if a woman is not having monthly periods, she should see a doctor.
Ovulation is when an egg is released from a woman’s ovary, usually about two weeks before her next period. Hormones released from the brain and ovaries cause ovulation and this normally occurs every month. For the next 24 hours after the egg’s release, the woman can become pregnant if the egg comes in contact with a male’s sperm.
Some of the reasons why ovulation may not happen are:
There a number of things that can reduce the quality or health of a woman’s eggs and that may reduce her chance of getting pregnant.
Some of these are:
Fig. 2 Female reproductive organs
The fallopian tubes (see Figure 2) connect the ovaries to the uterus. If the tubes become blocked this may stop the sperm meeting the egg which prevents a woman becoming pregnant.
Common causes of blocked tubes are:
It is not just the age of the woman that’s important when trying to have a baby. The quality or health of a man’s sperm decreases with age. This means it will take longer for a woman to get pregnant or she may not be able to get pregnant at all without assisted reproductive technology (ART) such as IVF.
The amount of semen that a man produces and the ability of sperm to swim or move forward towards an egg continue to decrease between the ages of 20 years and 80 years.
There are several problems that can occur with sperm that might affect a woman’s chance of getting pregnant. The sperm count (the number of sperm per ml of semen), sperm motility (the way the sperm moves or swims) and sperm shape can all impact on the chance of a woman becoming pregnant.
There are many factors that will affect the number and health of the sperm, these include:
Some causes of infertility may require medical or surgical treatment while others are related to lifestyle. These are some of the ways a couple can improve their fertility and chance of getting pregnant:
A couple should see a doctor if they are trying to get pregnant and:
It is also important for women to have a pre-pregnancy check up to make sure she is in the best health possible before she gets pregnant.
The doctor will ask questions about how long a woman has been trying to conceive and the couple’s medical history to help determine what test are required. Some common tests are:
There are a range of treatment options depending on the cause of the infertility.
For a woman:
For a man:
It’s not always possible to find the cause of infertility and in these cases IVF or other forms of ART may be the only option for a couple to become pregnant.
This is a general term used to describe ways to achieve pregnancy artificially or partly artificially. There are many different ways to do this and in vitro fertilisation (IVF) is one of the most common methods. In IVF the sperm and the egg are taken from the man and the woman and fertilised outside the body. The fertilised egg is then implanted in the woman’s uterus and she hopefully becomes pregnant.
Pregnancy and maternal health in: Australian Bureau of Statistics (2010) The health and welfare of Australia's Aboriginal and Torres Strait Islander peoples, 2010. (ABS Catalogue no 4704.0) Canberra: Australian Bureau of Statistics
Fertility Coalition (2013) Your fertility. Retrieved 9 October 2013 from http://yourfertility.org.au