O22. Correlation of sFlt-1/PlGF ratio with time to delivery or preterm birth in PROGNOSIS (prediction of short-term outcome in pregnant women with suspected preeclampsia study)

Abstract

Introduction PROGNOSIS reported a negative predictive value of 99.3% (95% CI 97.9–99.9) for ruling out preeclampsia/eclampsia/HELLP syndrome within 1week using a soluble fms-like tyrosine kinase 1 (sFlt-1)/placental growth factor (PlGF) ratio cut-off of 38 in women with suspicion of the syndrome. The sFlt-1/PlGF ratio may also help identify women likely to deliver preterm. Objectives Correlation of the sFlt-1/PlGF ratio with (a) time to delivery and (b) preterm delivery ( Methods PROGNOSIS (prospective/non-interventional) enrolled pregnant women ( ⩾ 18 years; gestational age 24wk+0d–36wk+6d at visit 1) with suspected preeclampsia (having clinical features of the syndrome). Maternal serum sFlt-1 and PlGF were measured (fully automated Elecsys ® sFlt-1 and PlGF assays; cobas e electrochemiluminescence platform; Roche Diagnostics, Mannheim, Germany) and analyzed at the study end. Assessment points: Visit 1; Visit 2 (7+2d); Visits 3, 4, and 5 (each 7 ± 2 d after previous visit); delivery; postpartum. Early and late gestational phases were defined as 24wk+0d–33wk+6d and 34wks to delivery, respectively. Cox-regression analysis was adjusted for gestational age and preeclampsia status. Results sFlt-1/PlGF ratio >38 at Visit 1 was associated with shorter time to delivery, particularly in the early gestational phase (Figure). With a median 15 (SD 11) day difference the immediate risk for delivery was higher for women with sFlt-1/PlGF ratio >38 versus ⩽ 38 (HR 2.9 [95% CI 2.5–3.5]), independent of preeclampsia status/gestational age. Women with sFlt-1/PlGF ratio ⩽ 38 had longer pregnancy duration (no preeclampsia [ n =720]: median 270 days, interquartile range [IQR] 262–279; preeclampsia [ n =91]: median 262 days, IQR 248–269) than in women with a ratio >38 (no preeclampsia [ n =159]: median 255 days, IQR 224–266; preeclampsia [ n =108]: median 251 days, IQR 232–262). These trends were consistent when the sFlt-1/PlGF ratio at any pre-delivery visit was examined (not shown). Women without preeclampsia, who had iatrogenic preterm delivery had a higher Visit 1 median sFlt-1/PlGF ratio (35.3 [IQR 6.8–104], n =171), than women with non-iatrogenic preterm delivery (8.4 [IQR 3.4–30.6], n =25) or term delivery (4.3 [IQR 2.4–10.9], n =584). For women who developed preeclampsia and delivered preterm, the median sFlt-1/PlGF ratio at Visit 1 was 121 (IQR 66.2–231, n =53). Conclusions The maternal sFlt-1/PlGF ratio gives further information on preterm delivery risk. Women with high sFlt-1/PlGF ratios (>38) should be closely monitored, regardless of preeclampsia.