What happens

An ultrasound picture is formed using sound waves, which are passed through the uterus and reflected back as an image. In most routine ultrasound scans, a special gel is spread on the lower abdomen (towards the bottom of your tummy) and then the scanner is moved over this until the uterus (womb) and pregnancy can be seen. If the pregnancy is smaller than about 10 weeks, or if it is difficult to get a clear picture with an abdominal scan, you may have a vaginal scan, where a probe is placed in the vagina.

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

Routine scans

Most pregnant women are referred for their first routine ultrasound scan somewhere between 12 and 18 weeks of pregnancy, in order to confirm that the baby is alive, to assess his/her size and growth, to estimate the delivery date and to check whether there is one baby, or twins or more. Some women may be offered a nuchal scan between 11 and 14 weeks. This measures the thickness of the fold at the back of the baby’s neck, which can indicate the likelihood of abnormalities such as Downs syndrome.

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” or “delayed” miscarriage. This can come as a considerable shock and it may take time before you can take this information in. You may feel the need to go away and return for another scan sometime later, just to be sure.

Early scans

You may be referred for an early scan, before 11 weeks, 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 is normally possible to see the baby’s heartbeat.

If the scan picks up a heartbeat and the baby appears to be the right size according to your dates, this can be very reassuring. Research has shown that if you see a heartbeat at 6 weeks of pregnancy, the chances of the pregnancy continuing are 78%. A heartbeat at 8 weeks increases the chance of a continuing pregnancy to 98% and at 10 weeks to 99.4%. So things could still go wrong, but as long as there is a heartbeat, the risk of miscarriage decreases as the weeks go by.

However, a heartbeat can be difficult to detect in early pregnancy so you may be asked to return for another scan a week or so later to assess the situation. Because of the time needed to make a clear assessment, many women experience a period of stress and uncertainty, of being “in limbo”, which can last for some time. You may need to find some support for yourself if this happens to you.

Other investigations

If there is no sign of a pregnancy in the uterus, you may be given a blood test to measure the levels of the pregnancy hormone ßHCG and possibly asked to return two days later for a repeat blood test. 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.