Condition category
Pregnancy and Childbirth
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status
No longer recruiting
Publication status

Plain English Summary

Not provided at time of registration

Trial website

Contact information



Primary contact

Mr I Mackenzie


Contact details

Nuffield Department of Obstetrics and Gynaecology
John Radcliffe Hospital
United Kingdom

Additional identifiers

EudraCT number number

Protocol/serial number

SPGS 757

Study information

Scientific title


Study hypothesis

The project is an RCT of the effect of first trimester ultrasound on rates of induction of labour for postdates. Currently it is widespread practice in most obstetric units in the United Kingdom to induce labour 14 days after the estimated date of delivery (EDD). While this has been shown to have a beneficial effect on perinatal outcome, it may cause consumer dissatisfaction as it is perceived to be a painful intervention in an otherwise normal pregnancy. Measurement of the biparietal diameter at 20 weeks gestation has been shown to improve the accuracy of gestational age assessment, and this should lead to a reduction in rates of induction of labour for postdates. Gestational age assessment using CRL in the 1st trimester is more accurate than the biparietal diameter and may further reduce the numbers requiring induction for postdates. There is an increasing shift to perform prenatal diagnosis in the first trimester. Those providing antenatal care may have to choose the best time at which a routine scan in pregnancy can be offered. If a first trimester ultrasound scan is shown to improve the customisation and therefore the appropriateness of obstetric care this would provide further evidence to justify its introduction as well as its use in screening for Down's syndrome, either with nuchal fold or as an adjunct to serum screening.
The objective is to determine whether an ultrasound scan in the first trimester of pregnancy will lead to more accurate assessment of gestational age and consequently lead to a reduction in the number of pregnancies induced at term and fourteen days. If this is the case then there will be cost savings for the NHS, as well as the reduction in unnecessary and potentially painful interventions.

Ethics approval

Not provided at time of registration

Study design

Randomised controlled trial

Primary study design


Secondary study design

Randomised controlled trial

Trial setting

Not specified

Trial type

Not Specified

Patient information sheet


Pregnancy and childbirth: Childbirth


The control group will continue with routine antenatal care with ultrasound performed for the usual indications.
The intervention group will have an ultrasound scan between 8 and 12 weeks gestation to measure the crown-rump length (CRL) and if there is a discrepancy of greater than 5 days between the estimated date of delivery (EDD) calculated form the last menstrual period and that by CRL the EDD will be revised to that derived by scan. The EDD will be entered in the patient's obstetric notes and all subsequent management decisions will be based on this assessment of gestational age.

Intervention type



Not Specified

Drug names

Primary outcome measure

Rates of induction of labour for postdates

Secondary outcome measures

1. The characteristics of labour with respect to the length of labour, the mode of delivery, the immediate perinatal outcome, analgesic requirements for labour and the overall client satisfaction with labour
2. Rates of gestation dependent events in pregnancy - false positive and negative outcomes from maternal serum screening
3. The management of early pregnancy complications

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

Women in the first trimester of pregnancy who do not require a first trimester ultrasound for any other clinical indication.

Participant type


Age group




Target number of participants

Added December 2008: 800 intended

Participant exclusion criteria

Women will be excluded if there is a clinical indication for a first trimester ultrasound scan or if they refuse consent. Examples of the former would be if there was vaginal bleeding, uncertainty about viability of the pregnancy or the possibility of an ectopic pregnancy.

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

Nuffield Department of Obstetrics and Gynaecology
United Kingdom

Sponsor information


NHS R&D Regional Programme Register - Department of Health (UK)

Sponsor details

The Department of Health
Richmond House
79 Whitehall
United Kingdom
+44 (0)20 7307 2622

Sponsor type




Funder type


Funder name

NHS Executive South East (UK)

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

Not provided at time of registration

Intention to publish date

Participant level data

Not provided at time of registration

Basic results (scientific)

Publication list

2006 results of uncompleted trial on

Publication citations

  1. Results of uncompleted trial

    Harrington DJ, MacKenzie IZ, Thompson K, Fleminger M, Greenwood C, Does a first trimester dating scan using crown rump length measurement reduce the rate of induction of labour for prolonged pregnancy? An uncompleted randomised controlled trial of 463 women., BJOG, 2006, 113, 2, 171-176, doi: 10.1111/j.1471-0528.2005.00833.x.

Additional files

Editorial Notes