18–20 week antenatal scan: low risk results

All women will be offered a 12 week dating scan and an 18–20 week mid-pregnancy scan also known as the ‘fetal anomaly’ scan.

The purpose of the 18–20 week mid-pregnancy scan is to check the baby is developing as expected and to look for any serious health conditions such as heart problems and spina bifida, and chromosomal conditions such as Edwards’ syndrome and Patau’s syndrome. This can help parents decide whether to continue the pregnancy. It can also identify problems that may benefit from early intervention following delivery and in some cases interventions that can be carried out during pregnancy.

Most people we talked to were broadly aware of this purpose. Some of them felt very well-prepared, while others would have liked more detailed information about what the scan looks for.

The information about what the 20-week scan was looking for was very thorough.

Age at interview 43

Gender Female

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One woman who had a scan in California felt that her doctor in the UK explained it better. Another suggested that the person doing the scan should check that the woman was properly informed. She noted that some scan technicians do a quick check for themselves before turning the screen round to face the woman, which may be a sensible precaution in case something is wrong.

The doctor in California who did her 20-week scan did not explain as well as her doctor in the UK.

Age at interview 23

Gender Female

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It would be sensible for sonographers at the 20-week scan to check the woman is properly informed…

Age at interview 36

Gender Female

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Some people saw the 18–20 week scan as somehow different to screening. They were not aware that terminations can be carried out at any stage of pregnancy where there is a severe abnormality.

She felt by the time of the 20-week scan it would be too late to consider ending the pregnancy.

Age at interview 33

Gender Female

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The 18–20 week scan reassures the vast majority of parents that their baby is fine. Women described many positive aspects, including:

  • The joy of seeing the baby and having a photograph
  • Feeling closer to the baby
  • Making the pregnancy seem real (especially for partners)
  • Finding out the baby’s sex, although this is not always possible or permitted

She really enjoyed seeing the baby at the 20-week scan. She would have liked to choose which…

Age at interview 26

Gender Female

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The 20-week scan was a moving experience and the person doing the scan explained everything very…

Age at interview 39

Gender Female

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One woman who had to have an internal scan (using a vaginal probe) because of the baby’s position found this did not spoil her enjoyment of the scan. For some people, having to have a full bladder, especially if the person doing the scan then pressed hard on their abdomen, was a minor drawback. Two people mentioned they had heard that the sound waves in a scan may distress the baby, but there is no conclusive evidence for this.

The 20-week scan was a lovely experience. She had an internal scan because of the baby’s position…

Age at interview 24

Gender Female

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Although most people said scans had made the pregnancy seem more real for their partners, for one father it was buying baby clothes that suddenly made it feel real. One mother felt the 18–20 week scan was an anticlimax after having seen the baby before. A few commented that the quality of the pictures was poor, but other people were impressed by the quality. This may depend on the type and age of equipment being used.

Although he enjoyed the 20-week scan, it was buying baby clothes that made the pregnancy seem real.

Age at interview 29

Gender Female

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The 20-week scan was reassuring but not as exciting as she expected, and the pictures were unclear.

Age at interview 32

Gender Female

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A very important concern for people was the way the person doing the scan (sonographer) communicated with them. Some people could compare different experiences: one woman had a senior consultant the first time, who was expert but brief, whereas the second time the scan was performed by a specialist midwife who recognised what an important emotional experience this is for parents.

Her first 20-week scan was professional but brief. The second time she had a specialist midwife…

Age at interview 29

Gender Female

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Some sonographers talk throughout the scan, explaining what they are looking at and whether it is as expected. This approach was preferred by virtually everyone we spoke to, including a French woman and her British partner who had their scan in France.

At her 20-week scan in France she was given detailed information and explanation. She and her…

Age at interview 28

Gender Female

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Staff who are talkative during a scan may suddenly go quiet if they notice something unusual, and this can create worry. Some staff explained that they would stay silent while they concentrated on the scan. Most people we talked to still felt they would rather know immediately if staff had seen something unusual.

They had an anxious moment at the 20-week scan when the sonographer paused briefly. They felt he…

Age at interview 33

Gender Female

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A moment of worry was described by a woman with previous experience of a scan which found the baby had died. She would have preferred a more immediate explanation.

When staff spotted something unusual during the 20-week scan, she was very anxious and would have…

Age at interview 43

Gender Female

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One person thought it must be difficult for staff to check if there is something they are not sure about if the woman is watching throughout.

It must be difficult for the person doing the scan to check something they are unsure about if…

Age at interview 44

Gender Female

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A few staff did not explain they would be silent, and this made some people worry. This is discussed further in the section 18–20 week scan: being told something may be wrong.

Not talking was sometimes more to do with pressure of work. One woman felt staff did not have much time to communicate properly and she came away anxious that something might have been missed.

Staff seemed uncommunicative on the day of her 20-week scan, and she felt anxious something might…

Age at interview 36

Gender Female

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Although some people had gone to the 18–20 week scan alone, most felt it was important to have someone with you for support. Two women said their partner had missed the scan because they were still trying to find a hospital car parking space.

Many experiences discussed here are common to other types of scan: see also Early dating scans and Combined screening for Down’s syndrome and other chromosomal abnormalities.

For further information on antenatal screening tests please see our pregnancy resources.

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