Fertility and Recurrent Miscarriage

Miscarriage Webinar

We recently held an insightful webinar with one of our fertility doctors, Dr Sotirios Saravelos, and Eloise Edington, from Fertility Help Hub. If you would like to learn about miscarriage in a Q&A video format, we highly recommend the webinar linked below.

What is miscarriage?

Miscarriage is defined as the spontaneous loss of a pregnancy during the first 23 weeks. 

The main sign of a miscarriage is vaginal bleeding, which is sometimes followed by lower abdominal pain and cramping. It’s important to note that light vaginal bleeding is common in the first trimester, and does not necessarily indicate a miscarriage. If you have any doubts, your GP or midwife should be the first port of call.

While miscarriage is not always openly discussed, it is quite common, affecting a significant proportion of women and couples. Miscarriages are often devastating events, and getting the right support could make a big difference in helping to heal and grieve following miscarriage. 

What is recurrent miscarriage?

Recurrent miscarriage is defined as three or more consecutive miscarriages, and affects around 1% of couples. Recurrent miscarriage is often traumatic, and tests can be advised to see if it is possible to identify the source of the problem and avoid future miscarriages. 

The UK national guidelines has historically recommended diagnostic tests after three miscarriages, although newer evidence, including European guidelines, have recommended targeted testing after two miscarriages to women and couples who wish to investigate sooner, or when it is clinically indicated.

What causes recurrent miscarriage?

Recurrent miscarriage has many possible causes. While it may not always be possible to find the source, some of the factors that the Royal College of Obstetricians and Gynaecologists associates with higher risk of recurrent miscarriage include:

• Increasing maternal age (and to a lesser degree, paternal age)

• Certain lifestyle factors such as smoking

• Antiphospholipid syndrome (APS), an acquired clotting disorder

• Inherited clotting defects

• Genetic factors, such as parental chromosomal abnormalities 

• Anatomical factors, such as congenital uterine malformations and cervical weakness

• Endocrine factors

• Immune factors

• Infections

What statistics do we have around the rates of miscarriage?

Up until the age of 35, it is believed that the chance of miscarriage is approximately 15%. That said, most worldwide studies on miscarriage use datasets with only confirmed pregnancies, for example done with a scan at a hospital. We know that a large number of miscarriages happen at home and/or are not reported, so the statistic is likely higher. 

Data does clearly show that the rate of miscarriage increases with maternal age and also increases with the number of previous miscarriages suffered. For example the lowest risk of miscarriage is in women aged 20-29, which is approximately 12%. However, in women over the age of 45 it can be as high as 65%. The reason for this is thought to be genetic; as women get older, egg DNA tends to be a bit more vulnerable, so when it pairs with the sperm, there can be genetic problems, such as unbalanced chromosomes.

Similarly, the risk of miscarriage is lowest in women with no history of miscarriage (11%), and then increases by about 10% for each additional miscarriage, reaching 42% in women with three or more previous miscarriages.

Treatment of recurrent miscarriage

In many cases (particularly with increasing maternal age), no specific cause is found and supportive care is predominantly offered. However, any abnormal findings can be treated and may lead to a significant improvement of future pregnancy success. These may include antithrombotic medication to treat APS, thyroxine to treat low thyroid function, surgery to treat uterine abnormalities and lifestyle modifications (such as stopping smoking and reducing alcohol intake) to improve egg and sperm quality.