Evaluation of Noninvasive Prenatal Testing (NIPT) guidelines using the AGREE II instrument.

The rapid increase of cell-free fetal DNA analysis for Down syndrome screening requires evidence-based clinical practice guidelines for noninvasive prenatal testing (NIPT). Several studies show that the quality of many guidelines is low and there are still many health areas where this quality is not systematically evaluated. Given the absence of research, in the NIPT field, we used an internationally validated tool to evaluate a set of three NIPT practice guidelines and to look at dimensions that can be improved.

Maternal serum alpha-fetoprotein in normal pregnancy at 11-13 weeks' gestation.

Objective: To establish a reference distribution of maternal serum alpha-fetoprotein (AFP) at 11-13 weeks' gestation and define the contribution of maternal variables that influence the measured concentration of AFP.

Methods: Serum concentration of AFP at 11-13 weeks was measured in 1,500 singleton pregnancies which were not complicated by hypertensive disorders or diabetes mellitus and resulted in the live birth at or after 37 weeks of phenotypically normal neonates with birth weights above the 5th and below the 95th percentile. Multiple regression analysis was used to account for maternal characteristics that influence the measured concentration of AFP and a distribution of log multiples of the median (MoM) values was fitted.