Maternal serum placental growth factor in prospective screening for aneuploidies at 8-13 weeks' gestation.

OBJECTIVE To investigate whether measurement of maternal serum placental growth factor (PLGF) can improve the performance of first-trimester combined screening for trisomy-21 by fetal nuchal translucency (NT) thickness and serum free β-human chorionic gonadotropin (β-hCG) and PAPP-A. METHODS In singleton pregnancies attending for routine care, serum PLGF, free β-hCG and PAPP-A were measured at 8(+0)-13(+6) weeks' gestation, and fetal NT was measured at 11(+0)-13(+6) weeks. The population included 12,154 normal and 44 trisomy-21 pregnancies. We examined the effect of adding PLGF on the performance of screening by the combined test. RESULTS In the trisomy-21 pregnancies the median multiple of the normal median PLGF, adjusted for gestational age, maternal weight, racial origin, smoking status and method of conception, was significantly reduced (0.6070, 95% CI 0.5543-0.6648), and this did not change significantly with gestational age. Adding PLGF to combined testing with a risk cut-off of 1 in 100 reduced the false positive rate from 2.7% (95% CI 2.5-3.0) to 2.6% (95% CI 2.4-2.8) and increased the detection rate from 85% (95% CI 75-93) to 88% (95% CI 78-95). CONCLUSIONS Inclusion of serum PLGF improves the performance of the first-trimester combined test in screening for trisomy-21.