P06.11: Normative values of fetal nasal bone lengths of Turkish singleton pregnancies in first trimester

Abstract

Objectives: 11–14 week scan and maternal serum markers are used mainly for fetal aneuploidy screening but their clinical implication in assessing the risk of other pregnancy complications has been being evaluated. Traditionally, fetal macrosomia is expected to manifest in later pregnancy but we assumed that it can be predicted earlier. The purpose of this study was to demonstrate the characteristics of the first trimester ultrasound and maternal serum biochemical markers for fetal aneuploidy in pregnancy with fetal macrosomia at term. Methods: We reviewed pregnancies in which 11–14 week scan had been performed and had delivered at term from July 2008 to February 2011. Total 772 pregnancies were included. Multiple pregnancies, pregestational diabetes, pregnancies with fetal growth restriction or major fetal anomalies were excluded. We divided them into 2 groups: macrosomia and appropriate for gestational age (AGA). Fetal macrosomia was defined as a birth weight above the 90th percentile for gestational age at birth. We compared MoMvalues of nuchal translucency (NT), maternal serum PAPP-A and free β-hCG, and crown-to-rump length (CRL) ratio measured at the time of 11–14 week scan in two groups. CRL ratio was the ratio between measured CRL and expected CRL of gestational age at ultrasonography. Results: Total 79 pregnancies (10.2%) were included in macrosomia group. Their MoM-value of PAPP-A was significantly higher than that of AGA group (median 1.26 MoM vs. 1.06 MoM, P = 0.03). CRL ratio was greater in macrosomia group (median 1.10 vs. 1.07, P = 0.03). MoM-value of free β-hCG was higher in macrosomia group which didn’t reach statistical significance (median 1.25 MoM vs. 1.05 MoM, P = 0.06). No difference was shown in MoM-value of NT between two groups. Conclusions: Some characteristics of fetal macrosomia can be demonstrated in the first trimester of pregnancy. 11–14 week scan and maternal serum markers for fetal aneuploidy have clinical implication in prediction of fetal macrosomia at term.