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PPO.01 EQUIPP: Evaluation of Fetal Fibronectin with a novel bedside Quantitative Instrument for the Prediction of Preterm birth
  1. DS Abbott1,
  2. NL Hezelgrave1,
  3. PT Seed1,
  4. PR Bennett2,
  5. M Chandiramani2,
  6. AL David3,
  7. J Girling4,
  8. JE Norman5,
  9. SJ Stock5,
  10. RM Tribe1,
  11. AH Shennan1
  1. 1Division of Women’s Health, Women’s Health Academic Centre, Kings College London, London, UK
  2. 2Department of Surgery & Cancer, Parturition Research Group, Imperial College, London, UK
  3. 3Institute for Women’s Health, University College London, London, UK
  4. 4West Middlesex University Hospital, Twickenham, UK
  5. 5University of Edinburgh, MRC Centre for Reproductive Health, Queen’s Medical Research Institute, Edinburgh, UK

Abstract

Introduction Fetal fibronectin (fFN) is a leading predictor of spontaneous preterm birth (sPTB) in high-risk asymptomatic women. As a positive/negative test (threshold of 50 ng/mL) the negative predictive value is high but positive predictive value (PPV) modest. The EQUIPP study aimed to determine if quantitative analysis of fFN (qfFn) improved prediction.

Methods A prospective masked observational study (n = 1387) of high-risk asymptomatic women who underwent qfFN testing between 22+0– 27+6 weeks’ gestation at 5 UK centres. Primary endpoint: sPTB <34 weeks’.

Results sPTB rate <34 weeks’ was 7.1%. Only 2.8% (26/941) of women with qfFN concentration < 10 ng/mL delivered <34 weeks’. The PPV for sPTB <34 weeks’ increased from 16.6%, 24.1%, 36.8%. 45.0% with increasing thresholds (10, 50, 200, and 500 ng/mL) respectively. Compared with qfFN <10 ng/mL, the relative risk of sPTB was 3.8 (95% CI, 2.3–6.6), 5.7 (3.2–10.0), 12.3 (7.3–20.8) and 16.3 (8.8–30.1) (p < 0.0001). The area under the Receiver Operating Characteristic curve for sPTB <34 weeks’ was 0.79 (0.74–0.84). Women with a short cervix on ultrasound (<25 mm) had a ten-fold increase in sPTB with qfFN concentration ≥200 ng/mL (18/45, 40%) vs. qfFN <10 ng/mL (3/68, 4.4%).

Conclusion qfFN provides alternative thresholds to define risk of sPTB compared with qualitative assessment. For high-risk women with qfFN <10 ng/mL (68% of cohort) risk of sPTB equalled background risk (3.3%) providing reassurance and potential discharge from intensive surveillance. qfFN ≥200 ng/mL offers improved positive prediction over conventional testing and is a valuable tool for risk assessment in women with a short cervix.

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