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Understanding Miscarriage

Updated: May 31, 2023

What is a miscarriage?

Miscarriage is very common in the first few weeks of pregnancy. Up to one in five women will have a miscarriage before 20 weeks, and most of these happen in the first 12 weeks. Miscarriage happens when a pregnancy stops growing, and the body expels the products of conception. Some women will have cramping, period-like pain and in most cases, there will be vaginal bleeding.

It is unlikely that if one miscarriage has occurred, a woman would miscarry again, and highly unusual for her to miscarry a third time. When women do miscarry three or more times (known as recurring miscarriages), tests can be done to look for a cause. Testing is not offered to women who miscarry once or twice because it is highly unlikely that anything will be found.

What causes miscarriage?

Usually, no treatable cause is found for a miscarriage. Research tells us that about half of all miscarriages happen because the chromosomes in the embryo are abnormal, and the pregnancy doesn’t develop properly from the start. In this case, miscarriage is nature’s way of dealing with an abnormal embryo.

Nothing can be done to prevent miscarriage if a pregnancy develops abnormally. However, there may be reasons why some women are at higher risk of experiencing a miscarriage:


Miscarriages are more common among older women than younger ones, largely because chromosomal abnormalities are more prevalent with increasing age.


Miscarriages are also more common among women who smoke and those who have more than three alcoholic drinks a week in the first 12 weeks of pregnancy. Research suggests that miscarriage is also more common among women who drink more than 500mg of caffeine a day or three to five cups of coffee.

Medical conditions

Some medical conditions in the mother, such as uncontrolled diabetes, fibroids or thyroid problems, can lead to miscarriage. Rare medical conditions that affect blood clotting can also cause miscarriage. Women who have three or more subsequent miscarriages should be tested for these conditions.

Diagnostic procedures

Early pregnancy tests, such as chorionic villus sampling (CVS) and amniocentesis, carry a small risk of miscarriage. These tests use a needle that is passed into the uterus. They are carried out only in women of advanced maternal age or to detect particular abnormalities more accurately.

Uterine and cervical abnormalities

Abnormalities in the shape of the uterus can lead to miscarriage. This tends to occur after 12 weeks because of a weakness in the neck of the uterus or due to implantation on a septum (divide of the uterus). Appropriate blood supply may not occur to these abnormal areas to support the growing fetus, resulting in miscarriage.

How to prevent miscarriage

Look after your general health – cut back on or eliminate smoking, modify your caffeine intake, abstain from alcohol and avoid contact with anyone who has a serious infectious illness. Usually, the next pregnancy will be normal but if you have three miscarriages in a row, further tests are recommended. Such testing would include investigation of parental chromosomes, excluding diabetes and thyroid disease, and/or hysteroscopy if miscarriages occur after 12 weeks gestation.

For couples experiencing recurrent miscarriages or failed IVF attempts, one option is Advanced Embryo Selection (AES) using Comparative Genomic Hybridisation (CGH) – an advanced technique used to test for genetic disorders. To learn more about this, please visit the Genetic testing (PGD) page on Dr David Wilkinson's website.

How to diagnose a miscarriage?

Women seek medical care at different stages of a miscarriage; sometimes the miscarriage has already happened and sometimes it has only just begun. A combination of symptoms (such as pain and bleeding), examination findings, ultrasound and blood tests will confirm whether you have had or are having a miscarriage.

A miscarriage is usually diagnosed as complete, incomplete or missed:

  • Miscarriage complete: This is when all the pregnancy tissue has passed.

  • Incomplete miscarriage: When some of the pregnancy tissue has passed but some is still inside the uterus.

  • Missed Miscarriage: This is when the pregnancy has stopped growing but the tissue has not passed, and there is still a “sac” in the uterus.

Pregnancy after miscarriage

You should attempt another pregnancy only when you feel both physically and emotionally ready and have undergone any necessary investigations to determine the cause of miscarriage, if possible. Most clinicians will recommend women have a normal menstrual cycle before attempting a subsequent pregnancy.

Coping with miscarriage

How you cope with miscarriage depends significantly on your personality and your situation. Every person is different, and the way that each individual deals with his or her own emotions are unique.

Coping with miscarriage involves finding the strength within yourself and within your relationship to get through this difficult period. It also involves asking for help when you need it.

While the medical focus may be on treating the physical causes of miscarriage, it’s equally important to take care of your emotional well-being. City Fertility has a team of counsellors and other trained staff who can help you deal with the stress and emotions involved in miscarriage and resolving fertility problems.

For more information to understand miscarriage, visit our recent blog.

To give yourself the best chance of falling pregnant, secure your spot at our Ready to Conceive Masterclass were our IVF and Fertility Expert Dr David Wilkinson will give you the lowdown on all things conception.

Couple dealing with miscarriage


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