ABSTRACT
Objetivos: Realizar tablas de referencia a través de estadística no paramétrica para definir en percentiles los rangos de normalidad del diámetro biparietal, la circunferencia cefálica, el atrio ventricular cerebral, la cisterna magna, el cavum septum pellucidum y los ventrículos laterales, según recomendaciones de la International Society of Ultrasound in Obstetrics and Gynecology de evaluación y medida. Métodos: Estudio transversal realizado desde enero 2014 a enero 2016. Se evaluaron 1004 embarazadas normales, en diferentes edades gestacionales, y de manera previamente estandarizada se midieron las estructuras mencionadas. El análisis estadístico se realizó con el software libre PAST 3.04 para la organización de los datos de cada edad gestacional en percentiles. Se presentaron en gráficos tipo nomogramas y en modelo de regresión polinómica de primer orden. Cada gráfico fue evaluado con significancia estadística con P<0,05. Resultados: Las estructuras intracraneales pudieron medirse en su totalidad en 864 casos (86 % de los exámenes). Los diámetros biparietal y las circunferencias cefálica pudieron obtenerse en todos los casos, se observó un crecimiento directamente proporcional a la edad gestacional (P< 0,05). La medida del atrio ventricular resultó estable lo largo del embarazo. Se presentan las medidas de la cisterna magna, del cavum septum pellucidum y de los ventrículos laterales. Conclusiones: Los rangos de normalidad se representaron en tablas para correcto uso clínico y de investigación, no difieren de investigaciones previas realizadas en otros países. Se presentan valores de referencia utilizables en la consulta prenatal, a través de estadística no gaussiana.
Objectives: To carry out reference tables through non-parametric statistics to define in percentile ranges of normality of the biparietal diameter, head circumference, the cerebral ventricular atrium, the cisterna magna, cavum septum pellucidum, and the lateral ventricles, according to the recommendations of the International Society of Ultrasound in Obstetrics and Gynecology of evaluation and measurement. Methods: A cross-sectional study was carried out from January 2014 to January 2016; 1004 normal pregnant women, in different gestational ages, were evaluated, and the mentioned structures, previously standardized, were measured. The statistical analysis was performed with the FOSS PAST 3.04 for the organization of the data at each gestational age, in percentiles. They arose in graphic type nomograms and first-order polynomial regression model. Each graphic was evaluated with statistics significance with P < 0.05. Results: The intracranial structures could be measured entirely in 864 cases (86% of the tests). Biparietal diameter and head circumferences were obtained in all cases; it was observed a directly proportional growth to gestational age (P < 0.05). The measurement of the ventricular Atrium was stable throughout the pregnancy. Measures of the cisterna magna, cavum septum pellucidum and of the lateral ventricles are represented. Conclusions: Normal ranges are represented in tables for correct clinical use and research, the results are not different from previous research conducted in other countries. Usable reference values, in the prenatal consultation, through non-Gaussian statistics are presented.
ABSTRACT
OBJECTIVE: To demonstrate that specificity to diagnose gestational diabetes increases when the end point diminishes from 180 to 170 mg/dL. MATERIAL AND METHODS: We made a transversal study based on the collection of 200 files randomly chosen, and whose diagnose was gestational diabetes identified by screening test. We established two end points: 180 and 170 mg/dL. The statistical analysis was based on the efficacy values for each one of them. Likelihood ratios for both tests were compared with the gold standard of the oral glucose tolerance test, 3 h with 100 g of glucose. A hundred patients were chosen for each group (the end point of the first and second group was greater than 180 and 170 mg/dL, respectively). RESULTS: The screening test results of the first group varied between 130 and 180 mg/dL. Fifty tolerance curves of four samples were negative and 50 were abnormal; 30 of these had diagnosis of gestational diabetes and 20 carbohydrate intolerance. In the second group the screening test results varied from 130 to 170 mg/dL. Sixty four tolerance curves of four samples were normal and 36 were abnormal; 24 of these had diagnosis of gestational diabetes and 12 carbohydrate intolerance. CONCLUSIONS: Modifying the superior end point of the glucose screening test, from 180 to 170 mg/dL, maintains the test sensitivity and improves its specificity.