How to Prevent a Miscarriage

By definition, miscarriage is the loss of a pregnancy before 20 weeks gestation, though 98% of miscarriages will occur in the first 13 weeks. Sometimes, miscarriage occurs even before a woman realises she is pregnant.

In Australia each year, it is estimated that around 55,000 women will experience a miscarriage. Statistically, this equates to around one in every four pregnancies not resulting in a live baby.

Although miscarriage is a relatively common event, it is still not well understood. Preventing it from occurring is not only difficult, but in many cases is almost impossible. Many researchers believe that miscarriage is nature's way of stopping an imperfect embryo from maturing. Miscarriage often results in cases where a congenital condition would be incompatible with life, there is embryonic deformity, a chromosomal defect or there has been an interruption to normal cell division.

It is currently thought that by far the majority of early miscarriages occur as a result of chromosomal interruption. However, there are certain risk factors which are known to increase the likelihood of miscarriage. Some are known as being modifiable, because to some extent, it is possible for a couple to change certain lifestyle factors which in turn reduce the overall risk of miscarriage.

Maternal Age

It is well known that a woman's fertility peaks in her early to mid twenties and decreases as she gets older. At birth, baby girls are born with all the eggs they will ever have. The quality of these eggs deteriorates over time, as well as the ability of a female's cells to produce sufficient energy in order to support cell growth soon after conception. Research has shown that the risk of having miscarriage is significantly lower in women aged 20-24, but in women who are 45 years of age or over the risk increases to almost 75%. Not only is it more difficult for women to conceive as they mature, carrying a baby to term becomes more difficult. The chance of conceiving a baby with a chromosomal abnormality also increases with age, as does the likelihood of having a multiple birth. It is not only the woman's age which has an impact either; her partner's age is also a factor. The combined age of a couple can be an indicator for the likelihood of carrying a baby to term.

Being Overweight

As difficult as it can be to acknowledge being overweight, it always pays to be honest. Many women prepare themselves to start the expensive process of fertility assistance, only to be told very early in their assessment phase to go home and lose weight. Not only does carrying too much fat reduce the chances of conceiving, having a Body Mass Index (BMI) more than 25, being overweight or obese also increases the risk of miscarriage. The chances of having pregnancy and delivery complications are also magnified when overweight. The risks of having recurrent miscarriages are also increased; it makes sense then to lose weight even before conceiving.

There is no magic answer to losing weight, other than eating less than your body requires for energy. Weight loss programmes, meal replacements, support groups and weight loss clubs all provide choice when it comes to how to lose extra kilograms. But the simple truth is that dieting does not work, nor is willpower a factor in successful weight loss. Carrying extra kilograms is often not so much about the food which is being eaten, as satisfying other emotional needs.


Smoking cigarettes is another modifiable risk factor. Although the number of smokers in society is less than previously, it is still an issue for many young people. Greater awareness of overall health risks and reduction in the numbers who even start smoking has meant that it is not as common.

Many women give up smoking when they are trying to conceive or stop abruptly when their pregnancy is confirmed. The benefits of ceasing begin to accumulate almost immediately after the last cigarette. It is worthwhile viewing the costs and effects of smoking not just on the lungs but the entire body, including the reproductive system.


Studies have found that drinking three or more units of alcohol per week in the first ten weeks of gestation increases the likelihood of miscarriage. It also increases the risk of having a stillborn baby. If you are planning to conceive or are already pregnant, you would be wise to adopt a no drinking stance. There is no level of alcohol which is considered safe for pregnant women and there are no health benefits to either you or your baby. Be imaginative about having other drinks which don t contain alcohol, such as soda or mineral waters, fruit juice, milk or soy alternatives.


Reduce your caffeine intake when you are pregnant. Research has shown that as little as two cups of coffee per day can double the risk of miscarriage. Cola drinks, chocolate, tea and energy drinks all contain caffeine as well. The current recommendation is that pregnant women need to limit their intake, but to what level is debatable. Some claim that one cup of coffee per day is safe; others say the only safe level is none at all. Discuss what is right for you with your health care provider.

General Health

Women who have pre-existing medical conditions such as heart disease, diabetes, hypertension or lupus are at an increased risk of having a miscarriage. If you are planning to conceive, make an appointment with your doctor to review your current health and management. Untreated chronic conditions not only reduce the likelihood of conceiving in the first place they also increase the likelihood of miscarriage.

For the majority of women, a miscarriage occurs only once and does not reduce the likelihood of being able to conceive again. Although it is normal to look for answers as to why it occurs, in the majority of cases, there is no definite reason why miscarriage happens. Very occasionally, the products of conception (blood and tissues) are sent to a laboratory for analysis. This tends to only happen when a woman has experienced multiple miscarriages and a genetic, chromosomal abnormality is suspected.


It is important that you see your doctor or midwife if you start bleeding at any stage during your pregnancy. Even if you feel you are alright, you would benefit from having a physical check. If you have a negative blood group you may need an injection of Anti-D which will help to protect your future babies.

Good Reading

  • Pregnancy Loss Surviving miscarriage and stillbirth: Zoe Taylor Harper Collins 2010
  • What to Expect Before You're Expecting- The complete preconception plan: Heidi Murkoff Harper Collins 2010


For more information and support, see your General Practitioner, midwife or health care professional. You can also visit or, or call the SANDS helpline on 1300 072 637.

16/09/21 - min Read

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