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Ultrasounds

Ultrasound scans in pregnancy may be routine or they may be offered because of pain or bleeding or because of problems in a previous pregnancy.

There are two ways of doing an ultrasound scan.

In early pregnancy, especially before 11 weeks, it is usual to have a trans-vaginal (internal) scan, where a probe is placed in the vagina.  This gives the clearest and most accurate picture in early pregnancy.  It may also be offered after 11 or 12 weeks if a trans-abdominal scan doesn’t give a clear enough picture.

From 11 or 12 weeks, including at the routine booking-in scan, it is more common  to have a trans-abdominal scan.  The person doing the scan spreads a special gel on your lower abdomen (below your belly button and above the line of pubic hair).  He or she then moves the scanner over the gel, sometimes pressing down, until the uterus (womb) and pregnancy can be seen.

What if I don’t want an internal scan?

If you don’t want a trans-vaginal scan, you can ask for a trans-abdominal scan. That may give some information about your pregnancy, but it is less clear than an internal scan and that could possibly delay diagnosis.

Can scans harm the baby?

There is no evidence that having a vaginal or an abdominal scan will cause a miscarriage or harm your baby. If you bleed after a vaginal scan, it will most likely be because there was already blood pooled higher in the vagina and the probe dislodged it.

When can I have a scan? When can you see the baby’s heartbeat?

An ultrasound scan may be able to detect a pregnancy and a heartbeat in a normal pregnancy at around 6 weeks, but this varies a great deal and isn’t usually advised.  All too often, a scan at 6 weeks shows very little or nothing, even in a perfectly developing pregnancy, whereas waiting a week or 10 days will make the findings much clearer.

Routine scans

Most pregnant women are referred for their first routine (or booking) ultrasound scan somewhere between 11 and 14 weeks of pregnancy.  The purpose of the scan is:

Some women may be offered a nuchal scan between 11 and 14 weeks. The purpose of this scan is to try to detect some chromosome abnormalities, such as Downs syndrome.

Many hospitals also offer a further anomaly scan at 20 weeks, making a more detailed check of the baby’s development.

You can find out more about routine, nuchal and anomaly scans at the website of the charity ARC – Antenatal Results and Choices

Sadly…

Sadly, sometimes these scans show that the baby has died, possibly some weeks earlier and often without any signs or symptoms such as bleeding or pain. This is often called a “missed”, “silent” or “delayed” miscarriage. This can come as a considerable shock and it may take time before you can take this information in.

You may also have to make some difficult decisions about how to manage the miscarriage process. You can read more about this here.

Early scans

You may be referred for an early scan because of vaginal bleeding or spotting, or possibly because you have had problems in a previous pregnancy.

The best time to have a scan is from about 7 weeks’ gestation when it should be possible to see the baby’s heartbeat in a normal pregnancy. But it can be hard to detect a heartbeat in early pregnancy and in those cases it can be hard to know whether the baby has died or not developed at all, or whether it is simply smaller than expected but still developing.

For that reason, you may be asked to return for another scan a week or so later.  At that time, the person doing the scan will be looking for a clear difference in the size of the pregnancy sac and for a developing baby and a heartbeat.

Sometimes, it can take several scans before you know for sure what is happening.  It can be very stressful dealing with this uncertainty – some women describe it as being “in limbo”.  You may need to find some support for yourself if this happens to you.

There’s a heartbeat, but I’m still bleeding…

If the scan does pick up a heartbeat and the baby appears to be the right size according to your dates, this can be very reassuring, even if you are still bleeding.

Research amongst women with a history of recurrent miscarriage has shown that those who saw a heartbeat at 6 weeks of pregnancy had a 78% chance of the pregnancy continuing.  It also showed that seeing a heartbeat at 8 weeks increased the chance of a continuing pregnancy to 98% and at 10 weeks that went up to 99.4%.

The numbers may be even more positive for women without previous miscarriages.

So things could still go wrong and sadly sometimes do, but as long as there is a heartbeat, the risk of miscarriage decreases as the weeks go by.

Other investigations

In some cases, if there is no sign of a pregnancy in the uterus, you may be given a blood test and possibly asked to return two days later for a repeat test.

These blood tests measure the level of the pregnancy hormone ßhCG. In a normally developing pregnancy the hormone levels double about every 48 hours and if the pattern is different, this can help to identify what is happening to the pregnancy.

If there is no sign of a pregnancy in the uterus and you have symptoms that suggest ectopic pregnancy, you are more likely to have both a blood test and an investigation called a laparoscopy, which is done under general anaesthetic. You can read more about this in our leaflet Ectopic pregnancy.

Scan results – and what they mean

The ultrasound scan may show:

In all of these situations, the pregnancy will fully miscarry with time, but there are several ways of managing the process. You may be offered a choice, or the hospital might make a recommendation. In most cases, you should be able to have time to think about what you can best cope with. You can read more here.

The ultrasound scan might show