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Los límites naturales de las pruebas de embarazo en relación con el período menstrual esperado
A J Wilcox1, D D Baird, D Dunson
1Epidemiology Branch, MD A3-05, National Institute of Environmental Health Sciences, Durham, NC 27709, USA. wilcox@niehs.nih.gov
JAMA
|October 12, 2001
Resumen
Las pruebas de embarazo pueden fallar en el 10% de los embarazos tempranos en el primer día de un período perdido. Para una detección temprana precisa del embarazo, considere la posibilidad de realizar pruebas una semana más tarde para una mayor sensibilidad.
Área de la Ciencia:
- Endocrinología Reproductiva y Reproducción.
- Química clínica es la química clínica.
- La reproducción humana es la reproducción humana.
Sus antecedentes:
- Las pruebas de embarazo estándar recomiendan su uso en el primer día de un período perdido.
- La detección temprana del embarazo está limitada por el tiempo de implantación del blastocisto.
- La variabilidad de la ovulación significa que el tiempo de implantación difiere en relación con la menstruación esperada.
Objetivo del estudio:
- Para estimar la sensibilidad máxima de detección de las pruebas de embarazo en el primer día de un período perdido.
- Para tener en cuenta la variabilidad natural en el momento de la ovulación y la implantación.
Principales métodos:
- Estudio de cohorte prospectivo basado en la comunidad en Carolina del Norte (1982-1986).
- 221 mujeres sanas de entre 21 y 42 años planificando la concepción.
- Muestras de orina en serie analizadas para la gonadotropina coriónica humana (hCG) para determinar el día de implantación en relación con las menstruaciones esperadas.
Principales resultados:
- El 10% (14/136) de los embarazos clínicos no habían implantado el primer día del período perdido.
- Se estima que la sensibilidad máxima de detección para las pruebas de hCG es del 90% en el primer día de un período perdido.
- La sensibilidad aumenta al 97% una semana después del primer día de la pérdida del período.
Conclusiones:
- El 10% de los embarazos clínicos no fueron detectables por ensayos de hCG altamente sensibles en el primer día de menstruación perdida.
- Las tasas reales de detección con las pruebas comerciales actuales pueden ser más bajas debido a las limitaciones del ensayo.
- La prueba una semana después de un período perdido mejora las tasas de detección de embarazo.
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