Efectivitat del cribratge bioquimic de segon trimestre i de l'ecografia de les 20 setmanes en el diagnòstic prenatal de les anomalies cromosòmiques i morfològiques fetals en una població general de gestants

Identificador:  TDX:637

Handle: https://hdl.handle.net/20.500.11797/TDX637

Autores:  Ros Campàs, Narcís

Resumen:
Congenital anomalies are currently the second cause of perinatal and infantile morbidity and mortality in Catalonia.The Catalan Programme of Prenatal Diagnosis of Congenital Anomalies, implemented in 1997, recommends: 1) biochemical screening using the double test (alpha-fetoprotein and β-hCG) to estimate the risks for both trisomy 21(T21) and open neural tube defects (NTD); 2) ultrasound screening by means of the anomaly scan at 20 weeks' gestation and 3) offering an invasive procedure to pregnant women with a high risk for chromosomal anomalies.Objective Evaluate the effectiveness of the Catalan Programme of Prenatal Diagnosis of Congenital Anomalies applied in the Health Plan for 1996-98 in a general population of pregnant women.HypothesisSecond trimester biochemical screening together with the anomaly scan at 20 weeks allow for the prenatal diagnosis of more than 60% of T21 and more than 50 % of detectable structural anomalies.Material and MethodsThis is a prospective cohort including all the fetuses screened by biochemistry or ultrasound in the public health system during a 3-year period.This is a population-based study, in which the study population was formed by the pregnant women attending the 5 health basic areas (ABS) assigned to the Hospital de Sant Pau i Santa Tecla of Tarragona.The fetal anomalies included in the study were all: 1.Clinically relevant chromosomal anomalies, in which termination of pregnancy may be considered as a means of secondary prevention to improve the perinatal and infantile morbidity and mortality;2.Detectable structural anomalies at the 20 weeks' scan (adopting the EUROCAT classification established by this European network of population-based registries for the epidemiologic surveillance of congenital anomalies)Structural anomalies were reanalyzed considering only the severe anomalies (as defined by Royal College of Obstetricians and Gynaecologists), in which termination of pregnancy may be considered as a means of secondary prevention to decrease the perinatal and infantile morbidity and mortality.Congenital anomalies have been ascertained by means of: 1) post-mortem reports in fetal demise or termination of pregnancy, and 2) neonatal examination and pediatric follow-up up to one year of life performed by local pediatricians (in the corresponding ABS). Thus, the effectiveness of the neonatal examination was also evaluated in the detection of those anomalies prenatally undiagnosed.Results1721 fetuses were studied, accounting for 62 % of the total population of the area during the study period. When applied, both screening methods allowed the prenatal diagnosis of 80% of T21, 100 % of NTD, 55% of detectable structural anomalies and 81% of severe structural anomalies. These rates were higher than expected according to previous studies.The detection rate achieved by the neonatal examination in the diagnosis of those prenatally undiagnosed was 100 % for T21, 67 % for clinically relevant chromosomal anomalies, 73 % for detectable structural anomalies and 88 % for severe structural anomalies.ConclusionsIn this population-based study, a high diagnostic capability was found for the two methods of prenatal screening regarding the most severe anomalies and would support the universal application of biochemical and ultrasound screening.