First‐trimester maternal serum biochemical indicators in Down syndrome

Abstract

A set of 21 early maternal serum samples (19 first‐trimester and two at 14 weeks) from pregnancies resulting in a child with Down syndrome was matched for gestation and length of storage with 63 samples from unaffected pregnancies. The concentrations of alpha‐fetoprotein (AFP), unconjugated oestriol (uE₃), human chorionic gonadotrophin (hCG), pregnancy‐specific β₁–glycoprotein (SP₁), and placental alkaline phosphatase (PALP) were measured. The ratios of the medians for Down syndrome pregnancies compared with the medians for controls were AFP 0·71, uE₃ 0·67, hCG 1·43, SP₁ 0·79, and PALP 0·92. Although the differences between the medians for affected and unaffected pregnancies were not significant, the trends for AFP, uE₃, and hCG confirm earlier findings on first‐trimester samples.