Falsos positivos del cribado de trisomía 21 y 18 del primer trimestre y complicaciones obstétricas / Adverse outcomes in pregnancies with false positive trisomy 21 and 18 screening results

RESUMEN

OBJETIVO: Analizar si los casos positivos de cribado combinado de trisomía 21 (t21) o trisomía 18 (t18) en ausencia de aneuploidía (falsos positivos- FP) se relacionan con complicaciones de la gestación, ajustando por factores demográficos y clínicos de riesgo. MATERIAL Y MÉTODOS: Estudio retrospectivo de casos y controles anidado en una cohorte de pacientes que acudieron para cribado del primer trimestre. Los casos fueron las pacientes con FP de riesgo combinado de t21 superior a 1/270 o riesgo de t18 superior a 1/100. Se consideraron complicaciones de la gestación óbito fetal, parto prematuro menor de 34 semanas o prematuro menor de 37 semanas, preeclampsia, retrasos de crecimiento, pequeño para la edad gestacional (CIR, PEG) y diabetes gestacional (DG). Se ajustó por obesidad, edad, paridad, tabaquismo, y técnicas de reproducción asistida. RESULTADO: Se obtuvieron 204 casos de FP, 149 FP para trisomía 21, 41 para trisomía 18, y 14 FP para ambos riesgos. Se encontró asociación estadísticamente significativa de FP t21 con óbito fetal (OR=3,5; ic95% 1,4-8,7; p=0,01), parto prematuro menor de 37 semanas (OR=2,2; IC95% 1,4-3,4; p=0,001), preeclampsia (OR =2,6; IC95% 1,17-6,1; p=0,02), PEG (OR =2,2; IC95% 1,2-4,1; p=0,02), CIR (OR=2,8; IC95% 1,6-5,1; p=0,001), y DG (OR=2,1; IC95% 1,2-3,7; p=0,01). Los FP t18 se asociaron con óbito (OR=8,9; IC95% 2,9-27; p=0,002). CONCLUSIÓN: Los FP del cribado del primer trimestre, para trisomía 21 y trisomía 18, se asocian con resultados obstétricos adversos.

ABSTRACT

We have studied whether positive cases of combined trisomy 21 (t21) or 18 (t18) screening in the absence of aneuploidy (false positives -FP-) are related to pregnancy complications adjusting for demographic and clinical risk factors. METHODS: Retrospective case-control study nested in a cohort of patients who came for first trimester aneuploidy screening. The cases were patients with FP combined risk of t21 (greater than 1/270) or t18 risk (greater than 1/100). The control group was a sample of patients with low-risk screening. We considered pregnancy complications stillbirth, premature delivery before 34 and 37 weeks, preeclampsia, growth retardation, small for gestational age (FGR, SGA), and gestational diabetes (GD). Or were adjusted for obesity, age, parity, smoking, and assisted reproduction techniques. RESULTS: 204 cases of FP were obtained, 149 FP for trisomy 21, 41 for trisomy 18, and 14 FP for both risks. A statistically significant association between t21 FP was found with stillbirth (OR = 3.5; 95% CI 1.4-8.7; p = 0.01), preterm delivery less than 37 weeks (OR = 2.2; 95% CI 1.4-3.4; p = 0.001), preeclampsia (OR = 2.6; 95% CI 1.17-6.1; p = 0.02), SGA (OR = 2.2; 95% CI 1, 2-4.1; p = 0.02), FGR (OR = 2.8; 95% CI 1.6-5.1; p = 0.001), and GD (OR = 2.1; 95% CI 1.2 −3.7; p = 0.01). FP t18s were associated with fetal loss (OR= 8.9 (95% CI 2.9-27) p = 0.002. CONCLUSION: FP from first trimester screening for t21 and t18 are associated with adverse obstetric outcomes.