OS065. Placental growth factor as a diagnostic and prognostic test forplacental complications of pregnancy

Placental growth factor (PlGF) levels in maternal circulation are altered in pre-eclampsia and intrauterine growth restriction (IUGR) (Benton et al.) and may have utility in identifying cases associated with placental dysfunction and stratifying pregnancy survival.

We sought to determine if a positive PlGF test measured on the Triage PlGF rapid assay (Alere, San Diego) agrees with the clinical diagnosis and predicts preterm delivery.

EDTA-blood was collected from women admitted to the AMC Obstetrics Department after 20 weeks of gestation with informed consent and according to the protocol approved by the AMC Medical Ethical Board (10/127). Plasma free PlGF levels from women diagnosed with early-onset pre-eclampsia (n=28), normotensive IUGR (N=6) and pregnancy complications excluding pre-eclampsia and IUGR (n=18) were quantified using the Triage PlGF immunoassay. Samples were collected before GA 34+6 and analyzed in batch assay. Results were interpreted against GA-dependent cutoffs set at the 5th centile for gestational age in normal pregnancy (Knudsen et al). PlGF levels below the cutoffs were assigned "positive" according to the product insert. The proportion of subjects with a positive PlGF test result was calculated for each group, together with the proportion of subjects requiring preterm delivery.

Twenty-eight women developed early-onset pre-eclampsia and, of these, 27/28 (96.4%) had a positive PlGF test. The woman with negative PlGF test presented to clinic at GA 34+3 with hypertension and suspected pre-eclampsia, but delivered at GA 39+4. Six women developed normotensive IUGR, of which 4 had a positive PlGF test, and in each the PlGF level was below the limit of detection of the test. The 2 women with a negative PlGF test had twin pregnancies. Eighteen women developed pregnancy complications excluding pre-eclampsia and IUGR. Six had at least one serial sample with a positive PlGF test. Of these, one woman had partial placental abruption, 3 had PPROM, one had spontaneous labour at GA 33+3, and one had bleeding after elective embryo reduction and neonatal death during delivery at 23+3. The proportion of women with a positive PlGF test, where the date of delivery is known, requiring preterm delivery was 34/37 (91.9%).

These preliminary data suggest that a positive PlGF test by Triage may identify placentally-mediated pregnancy complications and that a very low level of PlGF identifies women at increased risk for preterm delivery.