First trimester prediction of the 'small for gestational age' fetus

• Main Author: Karagiannis, Georgios
• Other Authors: Nicolaides, Kypros Herodotou
• Published: King's College London (University of London) 2016
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.733318

Objective: In this thesis, we investigate the association between maternal factors, biophysical and biochemical markers and the delivery of small-for-gestational-age (SGA) neonates in the absence of preeclampsia (PE) at 11–13 weeks’ gestation. We evaluate their performance as predictors of SGA, both in isolation and combined, in an effort to develop a model for the prediction of SGA in the first trimester of pregnancy. Methods: Screening study in 1,536 SGA and 31,314 non-SGA pregnancies based on maternal characteristics, fetal nuchal translucency (NT) thickness, serum pregnancy-associated plasma protein-A (PAPP-A) and free β-human chorionic gonadotrophin (β-hCG). We also measured mean arterial pressure (MAP), uterine artery pulsatility index (PI) and performed case-control studies for measurement of maternal serum concentration of placental growth factor (PLGF), placental protein 13 (PP13), A Disintegrin And Metalloprotease (ADAM12), Soluble endoglin (sENG) and thyroid hormones (thyroid stimulating hormone (TSH), free triiodothyronine (FT3) and free thyroxine (FT4)). Regression analysis was used to develop a model for the prediction of SGA. Results: In the SGA group, uterine artery PI and MAP were increased, serum PAPP-A, free β-hCG, PLGF, PP13, and ADAM12 and fetal NT were decreased while sENg and thyroid hormones were not significantly altered. At a false positive rate of 10%, the estimated detection rate by a combination of maternal factors and biophysical and biochemical markers at 11–13 weeks was 73% for SGA requiring delivery before 37 weeks and 46% for those delivering at term. Conclusions: Half of the pregnancies with SGA neonates in the absence of PE could potentially be identified at 11–13 weeks.