Maximising Natural Fertility

Women are naturally more fertile in their 20’s than their 30’s however there is a trend for couples to leave plans for pregnancy until later in their adult lives as compared to previous generations. Since 2000, 30-34 year olds consistently have the highest birth-rate of all age groups.

Frequent media reports of female celebrities conceiving later in life can lead to a perception that delaying pregnancy is without problems while in reality it can lead to difficulty conceiving, frustration and disappointment.

The effect of age on fertility: a female and male issue

Age is the most important factor in determining fertility. Women are born with all of their eggs already formed in the ovaries which are released throughout adult life. As women age so do their eggs and these eggs will eventually ‘run out’ or become of lower quality. This is why women usually find it harder to conceive after the age of 35 Years.

Women who are older also have higher rates of pregnancy complications such as miscarriage, gestational diabetes and stillbirth as well as a higher rate of genetic abnormalities including Down syndrome.

Men also experience a decrease in their sperm quality as they age. It can take a lot longer for a younger woman to conceive if her partner is over the age of 40 years with higher rates of miscarriage in pregnancies where the male is over the age of 45 years.

To maximise natural fertility, where practical, couples can consider planning for a pregnancy when they are younger rather than delaying until their mid-thirties or beyond when fertility rates decline. Some women may consider freezing their eggs if they do not have a partner but this can be a costly, invasive procedure. For further information on egg freezing:

Timing of sexual intercourse

Having sex every 2-3 days throughout the woman’s menstrual cycle, particularly during the week before ovulation, increases the likelihood of there being sperm already present in the female reproductive tract when the woman releases an egg from her ovary (ovulates). This will improve the chances of pregnancy.

The fertile window (the time in her cycle when a woman is most likely to conceive) is about five days before predicted ovulation until the day of ovulation. Most women will ovulate about 14 days before the next period. It can be helpful to use a calendar or smartphone app to track the menstrual cycle and work out when the fertile window is.

There are simple ovulation calendars available online. Other changes in the body such as a slight rise in body temperature, changes to the vaginal discharge (cervical mucous is runnier when a woman is fertile) and the use of ‘ovulation kits’ can help a woman to identify her fertile window.

Ovulation predictor kits can be bought from pharmacies and online. Ovulation kits predict ovulation by using either urine or saliva to detect hormone levels that indicate when ovulation is likely to occur. Although there is little evidence that they increase the chance of conceiving, they may be helpful to assist in timing of intercourse, although regular intercourse throughout the cycle is likely to be just as effective. The urine tests are thought to be more reliable than the saliva tests and both can be expensive.


Both being overweight or underweight can significantly affect fertility. Women who are either overweight or underweight may not ovulate. Women who are overweight also have higher risks of miscarriage and pregnancy complications such as high blood pressure and diabetes of pregnancy. Aiming for a Body Mass Index of between 20–25 kg/m2, eating a healthy, balanced diet with folate supplements and taking moderate exercise can improve natural fertility.


Smoking tobacco (including passive smoking) can decrease both female and male fertility. Men who smoke have higher rates of erectile dysfunction, a lower sperm count and sperm quality. In a woman, it is thought that the nicotine can interrupt the female hormones and smoking affects the transportation of the egg. Smoking in pregnancy can affect the placenta leading to higher rates of pregnancy complications, miscarriage and stillbirth and childhood asthma.

It is estimated that after 1 year of not smoking all of the negative effects have reversed.

Alcohol and drug use

The National Health and Medical Research Council recommends that for women who are pregnant, planning pregnancy or breastfeeding not drinking alcohol is the safest option.

When you are planning a pregnancy, it is also important to be aware that alcohol can reduce fertility in both men and women. Alcohol can greatly increase the time it takes to get pregnant and affect the quality of men’s sperm and women’s eggs. If you are trying to get pregnant you should consider not drinking alcohol at all ( ).

Recreational drugs, including cocaine, heroin, cannabis and ecstasy, have also been shown to affect male and female fertility and should be avoided.

When is it time to seek help?

Most healthy, fertile couples will conceive within 12 months of trying. If no pregnancy has occurred after 12 months (6 months if the woman is aged over 35 years), then it is advisable to see your GP or family planning clinic. If there are known or suspected fertility issues then seeking earlier advice is recommended.

For more information

The information in this Factsheet has been provided for educational purposes only. Family Planning NSW has taken every care to ensure that the information is accurate and up-to-date at the time of publication. Individuals concerned about any personal reproductive or sexual health issue are encouraged to seek advice and assistance from their health care provider or visit an Family Planning NSW clinic.

Delaying pregnancy can lead to difficulty conceiving, frustration and disappointment. Find out how to increase your fertility naturally.

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