What is a missed miscarriage?

A missed miscarriage is occasionally referred to as a silent miscarriage, and can be a very difficult experience to cope with. Many people assume that all miscarriages are signalled by a significant amount of bleeding and pain, however this is not always the case. Most Early Pregnancy Assessment Units around the country will be diagnosing several patients every day with a missed miscarriage, in other words, the embryo sadly has no heartbeat yet is still in situ in the uterus. Sometimes in this scenario women have begun to have symptoms that all is not well, but sometimes there is no indication prior to this that the foetus has stopped developing. Some women attend their first scan at 12 weeks having no idea that the baby has died some time ago, and need a lot of support following such an unexpected shock.

How is a missed miscarriage diagnosed?

A missed miscarriage is diagnosed during an ultrasound scan. Sometimes these are done abdominally (which requires a full bladder), however in the early weeks of pregnancy ultrasounds are usually performed trans vaginally (internally) which requires an empty bladder. During the scan the sonographer will be looking for a heartbeat, and also taking measurements of both the gestational sac and the embryo. If the embryo measures over a certain length from crown to rump but has no heartbeat, then a missed miscarriage can be diagnosed straight away, however if it is under a certain length, official guidelines state that the patient must be rescanned after a set period of time, usually either 7 days or 14 days to reassess if any further development has occurred including the heartbeat. These guidelines are to prevent mistakes being made and are set out by NICE (National Institute for Health and Care Excellence), because in some scenarios a pregnancy may simply be less further along than previously thought. Likewise, the dimensions of the sac, and whether or not a foetal pole (startings of an embryo) can be seen are crucial to whether or not a missed miscarriage can be diagnosed. For example, if the sac is over a certain measurement but a foetal pole is not seen at all then a miscarriage may be diagnosed straight away, however if the sac is smaller then a rescan will be booked at a later date to allow time to see if an embryo develops. The wait between scans can be very difficult for patients desperate for a diagnosis, however EPAU nurses do have to follow strict protocols regarding when they can rescan and they cannot speed up nature. A diagnosis of a missed miscarriage must be confirmed by a second sonographer in the UK.  

What are the symptoms of a missed miscarriage?

As mentioned above, many women have no symptoms at all to indicate that their baby has stopped developing. Other women may have started to bleed, or be experiencing some spotting or pain. Some women report that they notice general pregnancy symptoms such as nausea may suddenly stop or they don’t “feel” pregnant any more. Whilst these changes could indicate a possibility that things have stopped developing, isolated changes in symptoms rarely warrant a referral to an Early Pregnancy Unit because these symptoms are unpredictable in themselves and can often come and go randomly when a pregnancy is continuing to develop well.

When do you start bleeding during a missed miscarriage?

If an embryo has stopped developing, sooner or later your body will catch on and you will begin to bleed. However, when this will happen is very unpredictable. Some women begin bleeding straight away and pass the pregnancy sac within a few hours, other women do not, and it is not uncommon for a missed miscarriage to remain in situ in the uterus for several weeks. Some women who are diagnosed with a missed miscarriage at their 12 week dating scan find that the measurements of the embryo indicate that it is likely to have stopped growing several weeks earlier, despite the fact they have had not had any bleeding or reason to be concerned. If your pregnancy hormones remain high, you may also continue to experience symptoms such as morning sickness, even though the embryo has died. As your pregnancy hormones drop, bleeding is likely to start, however due to the unpredictable nature of when this will happen, many women opt for either surgery or a medical management to speed up the process.

Do you have to have treatment for a missed miscarriage?

Some women prefer to manage things conservatively and “watch and wait”. If you do not wish to have any intervention, your EPAU will probably offer you a follow up appointment after a couple of weeks where you may be rescanned and reassessed to see if anything has changed. During this waiting period many women do miscarry at home. If the pregnancy remains in situ for some time, your medical team will want to keep in touch with you to ensure that you remain well as the risk of infection can increase the longer the sac remains in the uterus.

If you do opt for some hospital management your EPAU will arrange this as soon as they can, although sadly due to NHS resources available, in some areas they may be a waiting period for a slot for your procedure.  See here for details of medical management of miscarriage and surgical management of miscarriage.

If your missed miscarriage is within the first few weeks of pregnancy and you are fit and well then the hospital will usually ask your personal preference as to how and if you would like intervention. If your missed miscarriage is further along, then some hospitals may advise a medical management over surgery.

Why have I had a missed miscarriage?

The Royal College of Obstetricians and Gynaecologists (RCOG) report that 1 in 5 pregnancies miscarry for no apparent reason. Even though with missed miscarriage the embryo is still in situ, it is very unlikely that any testing would be carried out to ascertain if for example there were any genetic problems in the embryo even after it has been passed vaginally or removed via surgery. However, women who suffer recurrent miscarriage may be offered cytogenetics testing.