PLANES: Placental Growth Factor Led Management of the Small for Gestational Age Fetus: A Feasibility Study

PLANES is a randomised controlled study to assess the feasibility and acceptability of using the sFlt-1/PIGF ratio to refine small for gestational age (SGA) pregnancy management pathways.

Being SGA during pregnancy is a common condition affecting 1 in 10 of all pregnant women. Although, if not managed with careful monitoring it has been shown to be related to stillbirth.

At present there is no treatment available and standard management consists of careful monitoring with ultrasound and fetal heart rate tracings and early delivery, typically around 37 weeks. Early delivery requires interventions such as induction of labour, when most of these babies are still healthy. It can also increase the risk of later health and developmental difficulties. Delaying delivery by even a few weeks could be of benefit to development. With reassurance of a baby’s health, it may be possible to safely prolong SGA pregnancies. Research studies using the biomarker sFlt-1/PlGF ratio, have shown that pregnant women with a normal ratio are very unlikely to have a stillbirth. As the sFlt-1/PIGF ratio provides information on placental function it could be used to monitor SGA affected pregnancies, allowing delivery to be safely delayed where indicated.

The PLANES study aims to assess the feasibility and acceptability to women and clinical teams of using the sFlt-1/PIGF ratio for the management of SGA pregnancies. Women will be randomised into two groups in a 3:1 ratio in favour of sFlt-1/PIGF ratio led management vs standard care. sFlt-1/PIGF ratio results will be used to determine the care pathway and timing of delivery in the sFlt-1/PIGF ratio led management group. Women with an SGA baby and a normal sFlt-1/PlGF ratio will have a repeat ultrasound and sFlt-1/PlGF ratio test every 2 weeks with a planned delivery delayed until 40 weeks. While those with an abnormal sFlt-1/PlGF ratio will be offered delivery from 37 weeks, or sooner if there are other concerning features on ultrasound. Women assigned to standard care will have an sFlt-1/PlGF ratio taken but the result will be concealed from the clinical team with their pregnancy being managed as per the local NHS hospital policy.

The results from the study will determine feasibility and inform the design of a future large randomised controlled trial powered for adverse pregnancy outcome.

Chief Investigator: Dr Andrew Sharp

Sponsor: University of Liverpool

Funder: National Institute for Health Research (NIHR) Research for Patient Benefit (RfPB)

Status: Recruiting