Standard care informed by the result of a Placental Growth Factor blood test versus standard care alone in women with reduced fetal movement at or after 36+0 weeks gestation: a pilot randomised controlled trial

Background
Biomarkers of placental function can potentially aid diagnosis and prediction of pregnancy complications. This randomised controlled pilot trial assessed whether for women with reduced fetal movement (RFM), intervention directed by measurement of a placental biomarker in addition to standard care was feasible and improved pregnancy outcome compared with standard care alone.
Methods
Women aged 16 – 50 years presenting at eight UK maternity units with RFM between 36+0 and 41+0 35 weeks’ gestation with a viable singleton pregnancy and no indication for immediate delivery were eligible. Participants were randomised 1:1 in an unblinded manner to standard care and a biomarker blood test result revealed and acted on (intervention arm) or standard care where the biomarker result was not available (control arm). The objectives were to determine feasibility of a main trial by recruiting 175 – 225 participants over 9 months and to provide proof of concept that informing care by measurement of placental biomarkers may improve outcome. Feasibility was assessed via number of potentially eligible women, number recruited, reasons for non-recruitment and compliance. Proof of concept outcomes included rates of induction of labour and Caesarean birth, and a composite 43 adverse pregnancy outcome.
Results
Overall, 2917 women presented with RFM ≥36 weeks, 352 were approached to participate and 216 (61%) were randomised (intervention n=109, control n=107). The main reason for not approaching women was resource/staff issues (n=1510). Ninety seven women declined the trial, mainly due to not liking blood tests (n=24) or not wanting to be in a trial (n=21). Compliance with the trial interventions was 100% in both arms. Labour was induced in 97 (45%) participants (intervention n=49, control n=48) while 17 (9%) had planned Caesarean sections (intervention n=9, control n=8). Overall, 9 (8%) babies in the intervention arm had the composite adverse pregnancy outcome versus 4 (4%) in the control arm.
Conclusions
A main trial using a placental biomarker in combination with delivery, as indicated by the biomarker, in women with RFM is feasible. The frequency of adverse outcomes in this population is low, hence a large sample size would be required along with consideration of the most appropriate outcome measures.