Accuracy of using crown rump length measurements in dating pregnancies

  • Research type

    Research Study

  • Full title

    The accuracy of using crown rump length in pregnancy: what should we be doing in IVF pregnancies and how relevant are the currently used Crown Rump Length measurements?

  • IRAS ID

    261506

  • Contact name

    L Stocker

  • Contact email

    l.stocker@soton.ac.uk

  • Sponsor organisation

    Southampton University Hospitals NHS Foundation Trust

  • Duration of Study in the UK

    3 years, 0 months, 1 days

  • Research summary

    It is not known how best to calculate the expected due date in In Vitro Fertilisation (IVF) pregnancies.

    Aim: to evaluate whether measurement of a baby's length on early ultrasound examination (usually done at 12 weeks of pregnancy) or known 'start' of an IVF pregnancy (egg collection dates (EC), are more accurate in calculating a due-date for IVF pregnancies.

    A measurement called the crown rump length (CRL) i.e. head-to-bottom length of the baby is currently used to calculate the age of the unborn baby at the 12th week of pregnancy. This CRL is compared to charts of babies' measurements from the 1970s using population data at this time These charts were made by measuring babies with now outdated ultrasound equipment.

    In order to do this we will look at existing data (retrospective observational) from hospital databases. We will look at babies measurements and other information which might affect the growth of their baby, from all women who have had IVF pregnancies conceived at Complete Fertility Southampton and Wessex Fertility Southampton (2011-2018). We will compare this to their delivery information. Knowing the delivery date, we will compare Estimated Due Date (EDD) as worked-out by the CRL of IVF pregnancies compared with the conception date from the IVF.

    The other aim would be to collect the measurements of unborn babies at 12-weeks of pregnancy which generates an EDD and compare this to their actual birth date, to see how good these old estimation charts still are. For this we would use the data of all women who have had a 12-week ultrasound scan at the Princess Anne Hospital (1998-2018) and then have gone into labour by themselves and delivered in the hospital. Again comparing EDD with actual birth date.

    We will also complete a staff and patient opinion survey.

  • REC name

    London - South East Research Ethics Committee

  • REC reference

    19/LO/1948

  • Date of REC Opinion

    2 Jan 2020

  • REC opinion

    Unfavourable Opinion