Investigating the Structured Use of Ultrasound Scanning for Fetal Growth

Fetal growth restriction during pregnancy represents one of the biggest risk factors for stillbirth (Gardosi et al, 2013), with 'about one in three term, normally formed antepartum stillbirths are related to abnormalities of fetal growth' (MBRRACE, 2015).

Therefore, antenatal detection of growth restricted babies is vital in order to be able to monitor and decide the appropriate delivery timing.

However, antenatal detection of SGA babies has been poor, varying greatly across trusts in England in those that calculate their rates (NHS England, 2016). Most trusts do not calculate their detection rates and rates are therefore unknown. It is estimated that routine NHS care detects only 1 in 4 growth restricted babies (Smith, 2015).

Oxford University Hospitals NHS Foundation Trust, in partnership with the Oxford Academic Health Science Network (AHSN) has introduced a clinical care pathway (the Oxford Growth Restriction Pathway (OxGRIP)) designed to increase the rates of detection of these at risk babies. The pathway is intended to increase the identification of babies who are at risk of stillbirth, in order to try to prevent this outcome, whilst making best usage of resources, and restricting inequitable practice and unnecessary obstetric intervention.

It has been developed with reference to a body of research, however, the individual parts of care provided have not been put together in a pathway in this manner before. Therefore it is important to examine whether the pathway meets its goals of improving outcomes for babies in a 'real world' setting.

The principles of the pathway are

1. A universal routine scan at 36 weeks gestation.

2. Additional growth scans at 28 and 32 weeks gestation based on a simplified assessment of risk factors and universal uterine artery Doppler at 20 weeks gestation.

3. Assessment of further parameters other than estimated fetal weight associated with adverse perinatal outcome (eg growth velocity, umbilical artery Doppler and CPR).

The clinical data routinely collected as a result of the introduction of the pathway offers a valuable and unique resource in identifying and analysing in the effects of the pathway on its intended outcomes and also in investigating and analysing other maternal, fetal and neonatal complications and outcomes, establishing normal / reference ranges for ultrasound values.