75 How useful is placental growth factor in routine practice? A clinical evaluation in women presenting with suspected placental disease

Introduction Placental growth factor (PlGF) is increasingly recognised as a marker of placental dysfunction. PlGF for the diagnosis of pre-eclampsia (PE) has recently been recommended by the NICE diagnostic assessment panel to rule out PE within one week but the significance of a positive test remains uncertain. Objectives The aim of this study was to evaluate the use of PlGF in routine practice in women with suspected placental disease with and without features of maternal disease. Methods Women with chronic disease (hypertension, renal disease±diabetes, n =114) with a change in maternal condition or women with suspected fetal growth restriction (FGR) ( n = 146) had a PlGF performed >20weeks. Results were revealed and standardised care pathways followed. Outcomes were checked by two independent reviewers. Results In line with previous reports, we observed a much shorter median test-delivery interval in women with a low PlGF n =61) and those with an intermediate PlGF 12–100pg/ml (19 [1–104]days; n =76), compared to those with a normal PlGF (40 [2–111]days; n =123). Despite a strong association between low PlGF and poor outcome (62% delivered 14days. 62% ( n =18) of these women had PE and 28% ( n =8) had FGR without maternal disease. There was no significant difference in the test-delivery interval between these groups (13 [0–37] compared with 11 [1–35]days, p >0.05). There were 2 false positive cases of low PlGF without a diagnosis of PE, however these women had confounding medical comorbidities which made the diagnosis ambiguous. Similarly, 2/77 women had a false positive intermediate PlGFs associated with concurrent maternal disease. There were no normal pregnancy outcomes associated with low PlGF. Evaluation of the 7 false negative cases (a diagnosis of PE with a normal PlGF) demonstrated that none were obtained within a week of delivery (27 [7–63]days). Three of these cases had long test-delivery intervals and 3 cases were complicated by complex maternal disease. Of the women with a normal PlGF and small for gestational age (SGA) ( n =51), the median test-delivery interval was 48 [4–90]days. However, 48/51 (94%) were >7days before delivery.9/51 of these normotensive SGA pregnancies with normal PlGF were delivered for suspected FGR (abnormal growth velocity, oligohydramnios and/or abnormal Dopplers) and had a median birthweight (BW) centile of 2.8 (0–8–8.3), 17 for suspected SGA (median BW centile 3.6 [0.1–9.6]) and 25 delivered for other reasons (median BW centile 5.25 [1–9.3]). There were 3 cases of stillbirth, one of which had a normal PlGF (23days before delivery; BW centile 1.4). Conclusion In our cohort, a low PlGF was universally associated with a poor outcome and short test-delivery interval which was not affected by the indication (maternal or fetal) for the PlGF. Our evaluation confirms the value of PlGF as a diagnostic tool for placental dysfunction, however it has highlighted that several evidence gaps remain before this test can be implemented in routine clinical practice and confirms that abnormal PlGF levels in isolation are not an indication for delivery. Further research linking placental pathology and maternal PlGF levels is urgently needed.