Early-onset preeclampsia (PE) screening in the first trimester is currently possible, allowing preventive treatments to be applied. Several ultrasound characteristics related to the size and volume of the placenta have been evaluated in the first trimester, finding a significant association with the risk of developing PE or foetal growth disorders. However, none of the multivariate screening algorithms currently used include first-trimester placental variables. The main objective of this project is to analyse the diagnostic performance of placental biometry in the first trimester for the screening of placental insufficiency, in isolation and combined with other maternal, biochemical and biophysical variables. Likewise, the determining factors of placental size in the first trimester will be evaluated, as well as the relationship between placental size and volume, and maternal and obstetric characteristics and perinatal outcome._x000D_ The main outcome variables were the diagnosis of PE or foetal growth disorders (intrauterine growth restriction or small for gestational age (SGA)). Data were analyzed individually for each of these variables, and grouped as composite outcome variables according to severity criteria. All variables were adjusted by gestational age. First, an intra- and interobserver study of placental variables was carried out to assess the reproducibility of the measurements, and first trimester reference tables were prepared for each of them. Next, a correlation analysis and a bivariate analysis were performed to evaluate the relation between first and second trimester placental biometry, and maternal characteristics, biochemical variables (pregnancy associated plasma protein-A (PAPP-A) and placental growth factor), and biophysical variables included in the study._x000D_ A total of 1340 women were included in the study. Intra- and interobserver analysis showed a good reproducibility of placental measurements in the first trimester. A positive correlation was found between placental biometry and the biochemical variables studied, and there was a negative correlation with uterine artery Doppler. There was also a positive correlation between placental size and volume in the first trimester and neonatal and placental weight at birth. Compared to women without PE, women with severe adverse perinatal outcomes related to placental insufficiency had lower first-trimester thickness and placental volume. However, there were no differences compared to women with term PE. Women with SGA foetuses had smaller placental measurements, although differences with respect to basal and corionnic plate did not reach statistical significance. Among the prediction models analyzed for the composite outcome variables, the highest diagnostic performance was obtained for the model including maternal, biochemical (PAPP-A), biophysical variables and all 2D and 3D ultrasound placental variables. _x000D_ First trimester placental biometry, in the context of a multivariate screening, is useful in the early detection of pregnancies at risk for placental insufficiency, especially for SGA. The screening models analyzed in this study showed a good capacity for discrimination, but this was lower than that of the multivariate systems currently used in clinical practice. This suggests that the incorporation of placental variables in PE screening and its complications is unlikely in our environment.
Biometría placentaria para predecir el riesgo de preeclampsia y alteraciones del crecimiento fetal
Trilla Solà, C. (Author). 4 Nov 2022
Student thesis: Doctoral thesis
Student thesis: Doctoral thesis