Early first-trimester maternal serum placental growth factor in trisomy 21 pregnancies

To measure maternal serum placental growth factor (PlGF) levels in trisomy 21 cases and controls in samples drawn before 11 weeks' gestation.

Early first-trimester maternal serum samples, drawn between 8 + 0 and 10 + 6 weeks' gestation, for 37 trisomy 21 cases and 244 unaffected controls were retrieved from frozen storage, and PlGF was retrospectively measured using a DELFIA Xpress immunoassay platform. PlGF levels were converted to multiples of the median (MoM), and trisomy 21 and unaffected groups were compared.

Raw PlGF and MoM levels were significantly higher in the maternal serum of trisomy 21 cases than in controls over the 3-week gestational window (unaffected 1.0 MoM compared with trisomy 21 1.3 MoM (P < 0.0001)). However at 8 completed weeks of gestation the increase was most significant and at 10 completed weeks there was no significant difference between trisomy 21 and unaffected PlGF levels.

Early PlGF levels in maternal serum in trisomy 21 cases may be increased relative to unaffected controls, however, the relationship between PlGF levels and gestational age in trisomy 21 and unaffected pregnancies in the first two trimesters of pregnancy appears to be complex and requires further study.