Understanding miscarriage

Miscarriage, or the loss of a pregnancy in the first 20 weeks, is not uncommon. In Australia, it’s estimated that around one in five confirmed pregnancies end in miscarriage, and even more women miscarry without knowing they were pregnant in the first place. The risks are highest in the early stages of pregnancy, especially in the first trimester (up to 12 weeks), which is why many couples choose to wait until passing this stage of pregnancy before sharing their news more broadly.

Going through a miscarriage can be devastating. There is no right or wrong way to feel and it’s normal to experience a range of emotions. Many women and their partners require support through this difficult time – there are support services for people dealing with miscarriage, or you can speak to your doctor for advice. While it can take time to recover from the loss of a pregnancy, it’s important to remember that most women who miscarry will go on to have a healthy pregnancy in the future.

What causes a miscarriage?

There are two broad requirements for a successful pregnancy. Firstly, the embryo (or developing baby) needs to be healthy, which largely depends on the health of the egg and sperm. Secondly, the mother’s body – particularly her uterus and fallopian tubes – must be able to establish and carry a pregnancy.

If something goes wrong with any of the steps that are needed for a healthy pregnancy, it can result in miscarriage. It’s important to note that almost always, the factors that lead to loss of a pregnancy are outside of the mother’s control. So, it might help to think of these as reasons a miscarriage occurred, rather than causes.

For example, one of the most common reasons for a pregnancy ending is that the embryo has an abnormal genetic make-up (e.g. too many or too few chromosomes), which eventually prevents the baby from progressing through the normal stages of development. This can happen by chance at conception – when the sperm fertilises the egg – and there is nothing that can be done to prevent the miscarriage.

In other cases, the pregnancy may not be viable if the embryo fails to implant into the uterus wall, because this means the baby can’t get the nutrients it needs to grow properly. Generally speaking, a single miscarriage is considered relatively normal, and the next pregnancy will most likely be successful.

What factors increase the risk of miscarriage?

We know that as women age, their rate of miscarrying increases (see Figure 1). This is due to a decrease in the quality of a woman’s eggs as she ages, with more eggs having chromosomal abnormalities. Likewise, as men age they start to produce more abnormal sperm, which can have genetic defects. Both of these factors increase the chance of having a baby with a genetic abnormality that leads to miscarriage. So, if either parent is older – e.g. the mother is over 35 or the father is over 45 – and the couple has a miscarriage, it may be worth seeking specialist fertility help as early as possible.

Another scenario where a sole miscarriage may be of concern is when a couple has been trying to get pregnant for a long time, and then they lose the pregnancy. The initial struggle to get pregnant may indicate that there is an underlying issue preventing successful pregnancy, so the sooner expert help is sought, the better.

Maternal age miscarriage rate (%)

Other factors that increase the chance of having a miscarriage include:

  • Smoking
  • Serious infections and high fever
  • Hormonal imbalance
  • Anatomical abnormalities (e.g. of the uterus, fallopian tubes or cervix)
  • Chronic diseases such as diabetes, lupus or PCOS.

It’s also important to limit alcohol consumption and reduce your caffeine intake to one coffee per day if you are trying to become pregnant.

Seek medical help for multiple miscarriages

When a woman has three miscarriages in a row, with no normal pregnancy in between, we call this ‘recurrent miscarriage’. When multiple, continuous miscarriages occur, it is more likely that there is a specific reason the pregnancies are unsuccessful. If this happens to you, it’s important to seek the help of a fertility specialist, who will try to determine the cause, and whether it is treatable. While it is common for women to suffer from miscarriage, recurrent miscarriage only affects around 1% of couples.

Speak to a specialist

When dealing with a miscarriage, the uncertainty around your likelihood of a healthy pregnancy in the future may be distressing. If you have suffered a miscarriage or you’re at heightened risk of miscarrying and need the help of a specialist, please make an appointment by calling (03) 9418 8299 or book online.


The information on this page is general in nature. All medical and surgical procedures have potential benefits and risks. Consult a healthcare professional for medical advice specific to you.


Back To Top