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Understanding our advice ~ February 2004

Routine ultrasound scanningbefore 24 weeks of pregnancy


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Routine ultrasound scanning before 24 weeks of pregnancy

Purpose of this documentNHS Quality Improvement Scotland (NHS QIS) has issued Advice to

NHSScotland on the use of routine ultrasound scanning before 24 weeks

of pregnancy. The Advice considers clinical and cost effectiveness, and

organisation of services in Scotland.

We have advised NHSScotland that each pregnant woman in Scotland

should be offered an ultrasound scan in both the first and secondtrimesters of pregnancy.

This brochure has been produced to explain our Advice on routine

ultrasound scanning to people who do not have specialist knowledge in

this area.

It explains what the Advice means for women who have undergone, or

may have to undergo, ultrasound scanning, how we formed the Advice,

and what values we applied to the evidence about ultrasound scanning.

The full evidence is discussed in detail in Health Technology Assessment 5:

Routine ultrasound scanning before 24 weeks of pregnancy.

The words in bold are explained in the Glossary at the end of this

document.

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What is ultrasound scanning?Ultrasound scanning uses high frequency sound waves to create a picture

of the fetus during pregnancy. Scans provide information about the size

of the fetus, the date the baby is due, and its development. Scans can

also identify multiple pregnancies, for example twins.

In the first trimester ultrasound measurements can be combined with the

results of a blood test from the mother (called a serum screen). Thismeasurement can be used to identify the risk of a baby having a disorder

such as Downs syndrome.

Ultrasound scanning in the second trimester can detect a number of

serious problems including heart defects and spina bifida.

Ultrasound scans will not pick up every problem.

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Service in ScotlandUltrasound scanning is part of routine antenatal care in Scotland and

each year over 50 000 pregnant women are offered scans. Practice varies

throughout the country, however, and ultrasound scanning is provided in

different ways at different hospitals. Women are being offered ultrasound

at different stages of pregnancy, and undergo different types of tests to

assess the potential risk of conditions like Downs syndrome and spina

bifida. Most women in Scotland are currently offered only one routinescan, usually during the first trimester.

We have looked at the benefits and risks of using ultrasound scanning in

the first 24 weeks of pregnancy and recommend that all pregnant

women should be offered two routine scans.

The first scan should be offered in the first trimester to determine the

duration of pregnancy (gestational age) and identify potential problems

with development of the fetus. Women should also be offered a screening

test to identify the risk of Downs syndrome where ultrasound

measurements will be taken (known as nuchal translucency measurement)

and combined with the results of a blood test from the mother. This test

needs to be carried out between 10 and 13 weeks of pregnancy.

A follow-up test will be offered to a woman if she is found to have a higherchance of having a baby with Downs syndrome. There is a small risk that a

woman may have a miscarriage as a result of these follow-up tests.

The second ultrasound scan, called an anomaly scan, should be offered

in the second trimester at between 18 and 22 weeks to identify certain

fetal defects.

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We have advised that pregnant women should be told exactly whatultrasound can and cannot detect so they can make an informed decision

about whether or not to have ultrasound scanning. We have also advised

that they should be provided with appropriate written information and

given the opportunity to discuss issues or questions they may have before

their first scan.

Pregnant women are not required to have these scans and can choose to

take part in some, all or none of the scanning programme. Those who

decide to take part will be asked to provide written consent for some tests.

Our advice should ensure that all pregnant women are offered a scanning

and screening service that is:

properly explained to them and only done with their

informed consent

as safe as possible for them and their babies

as accurate as possible, while ensuring the least number of

follow-up tests

provided consistently throughout Scotland

based on the latest evidence.

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How we formed our AdviceWe used an internationally recognised process called Health Technology

Assessment to form our Advice. The assessment took account of the

social, ethical, medical and economic implications of routine ultrasound

scanning before 24 weeks of pregnancy.

It brought together:

scientific evidence e.g. articles published in medical or scientific journals

(journal articles)

+

expertise of health professionals

+

needs and preferences of pregnant women while considering the way

NHSScotland is organised and how pregnant women are currently

managed.

We worked with a group of doctors, obstetricians, sonographers,

midwives, nurses and pregnant women to look at all the evidence. The

evidence was recorded in a consultation report. Comments received

during consultation were published on the web and taken account of in

our scientific document, the Health Technology Assessment Report, and

our Advice to the health service in Scotland.

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Evidence usedWe gathered evidence from around the world. We use the word

evidence to include information collected from a variety of sources, and

we use different types of evidence to answer different types of questions.

For example:

Issues for pregnant women

What information needs do pregnant women have? Do they understand

what the findings of a scan mean?

Evidence came from journal articles and discussion groups with pregnant

women.

Clinical effectiveness

What is the most clinically effective use of ultrasound scanning? When

should pregnant women undergo a scan?

Evidence came from journal articles, studies and manufacturers.

Costs and benefits

How much does ultrasound scanning equipment cost? What savings can

be made from the earlier diagnosis it can provide and what are the

benefits e.g. the reduced need for further invasive tests?

Evidence came from studies we made on costs and savings, and

information about clinical effectiveness.

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Organisational issues

What ultrasound scanning services are currently provided in Scotland? Do

staff who provide ultrasound scanning have the appropriate training?

Evidence came from studies and a national survey we undertook.

The following diagram is an example of how all four types of evidence

came together to help form our Advice.

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Clincal Effectiveness

Ultrasound scanning can accuratelyestimate date of delivery and allows

early diagnosis of multiplepregnancies. It is also an effective

method of identifying potentialproblems during pregnancy. For

example, a nuchal translucency scan,combined with a blood test, can

identify a risk of Downs syndrome

;

;

Advice

All pregnant women inScotland should be offered

both a first and secondtrimester scan. Appropriatewritten information shouldbe provided to women and

an opportunity given todiscuss ultrasound scanningwith a health professional

prior to the first scan.

Cost and Benefits

Introducing two ultrasound

scans for all pregnant women

increases costs but a nuchal

translucency scan may reduce

the need for follow-up tests

and a second trimester scan

can identify defects.

Organisational Issues

Ultrasound scanning should

be performed by formally

trained staff.;

Issues for

Pregnant Women

Ultrasound scanning reduces

anxiety and early screening

provides reassurance for the

majority of pregnant women

about their babys health.

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Sources of support and informationIf you, or your partner is due to undergo an ultrasound scan then you

can discuss this Advice with your doctor or midwife.

Further information about pregnancy and childbirth is available from the

National Childbirth Trust (www.nct-online.org), tel. 0870 444 8707.

The NHS QIS Advice to NHS Scotland, Health Technology AssessmentAdvice 5: Routine ultrasound scanning before 24 weeks of pregnancyand

full scientific report, Health Technology Assessment Report 5: Routine

ultrasound scanning before 24 weeks of pregnancyare available from NHS

QIS or its website, www.nhshealthquality.org.

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Glossary

Advice Evidence-based recommendations made by NHS QIS

about any aspect of healthcare including medicines,

devices, clinical procedures, and healthcare settings. NHS

Boards and health professionals are expected to take

account of NHS QIS Advice when making decisions about

services for patients.

Clinical effectiveness The evaluation of benefit against risk in a standard clinical

setting using outcomes of importance to the patient.

Downs syndrome A lifelong disorder, which exists before birth, where the

baby has an extra chromosome.

Health technology An intervention used to promote health; prevent, diagnose

or treat disease; or provide rehabilitation or long-term

care. This includes medicines, devices, clinical procedures

and healthcare settings.

Fetus The unborn baby from the end of the eighth week after

conception (when the major structures have formed) until

birth.

NHSScotland The National Health Service in Scotland.

Nuchal translucency A measurement of the space between the skin and thebone in the fetal neck (taken at 10 to 13 weeks of the

pregnancy).

Obstetrician A doctor who specialises in the care of pregnant women

and delivery of babies.

Serum screening Measurement of markers present in the blood to give an

estimate of the risk of potential abnormalities.

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Sonographer A health professional who carries out ultrasound scans.

Spina bifida A birth defect of the spinal column where part of the

spinal cord is exposed.

Trimester The nine months of pregnancy is traditionally divided into

three trimesters: distinct periods of roughly three months

in which different phases of development take place.

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NHS Quality Improvement Scotland (NHS QIS)Our role is to improve the quality of healthcare in Scotland. We provide

clear, authoritative advice on effective clinical practice, set national

standards and monitor and publish reports on performance. We also

advise on health interventions that are value for money, commission

clinical guidelines and support the implementation of clinical governance.

To advise on value for money, we must balance how well a treatment

works with how much it costs.

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FeedbackUnderstanding our Advice aims to explain the work of NHS QIS in a

way that everyone can understand. We would warmly welcome feedback

on this brochure. For example, have we clearly explained our Advice on

routine ultrasound scanning before 24 weeks of pregnancy, and do you

have any questions that that were not answered here? Please give

feedback to Rob MacPhail, Communications Officer, NHS Quality

Improvement Scotland, Delta House, 50 West Nile Street, GlasgowG1 2NP, tel. 0141 225 6992, email: [email protected]

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NHS Quality Improvement Scotland, February 2004

ISBN 1-903961-45-9

First published February 2004

NHS Quality Improvement Scotland consents to the photocopying,

electronic reproduction by uploading or downloading from the

website, retransmission, or other copying of this document for the

purpose of implementation in NHSScotland and educational and not forprofit purposes. No reproduction by or for commercial organisations is

permitted without the express written permission of NHS Quality

Improvement Scotland.


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NHS Quality Improvement Scotland

Glasgow Office~ Delta House 50 West Nile Street Glasgow G1 2NP Tel 0141 225 6999

Edinburgh Office~ Elliott House 8-10 Hillside Crescent Edinburgh EH7 5EA Tel 0131 623 4300

[email protected] www.nhshealthquality.org

This document is produced from elemental chlorine-free material and is sourced from sustainable forests

This document can be viewed on the NHS QIS website. It is also available, on request, fromNHS QIS in the following formats:

Electronic

Audio cassette

Large print

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