RESUMENObjetivo: Comparar la edad gestacional, el peso y tipo de parto de recién nacidos atendidos en el sistema público y privado de salud, Concepción, Chile. Método: Se incluyeron 2.540 recién nacidos de embarazos únicos, entre las 28 y 42 semanas, desde octubre de 2004 a julio 2005; 1.531 pertenecientes al sistema público y 1.009 del privado. Se utilizó el sistema de salud como variable independiente y la edad gestacional, peso y tipo de parto, como variables dependientes. Resultados: La tasa de prematurez en el sistema público fue significativamente mayor (10,68% vs 5,32%), como también el peso neonatal promedio menor (2.383 g vs 2.786 g). Los recién nacidos de término del sistema privado tuvieron peso promedio al nacer inferior (3.326 g vs 3.458 g). La tasa global de cesárea fue 51,8%; 81% en el sistema privado y 32,6% en el público. En el sistema privado el 55,4% fueron cesáreas electivas y 63,1% de ellas realizadas entre las 37 y 38 semanas. Conclusión: El acceso de pacientes beneficiarias del sistema público al sistema privado, aparece como un avance en lograr igualdad en salud, pero eso no se refleja en mejores resultados perinatales y en la tasa de cesáreas.PALABRAS CLAVES: Desigualdad en salud, tasa de cesárea, sistema público de salud, sistema privado de salud SUMMARY Aims: To compare the gestational age, weight and delivery of newborn belonging to public and private health system, Concepción, Chile. Method: This study included 2540 newborn from the same number of pregnant woman with gestational age between 28 and 42 weeks from October 2004 to July 2005; 1531 newborn from public and 1009 from private health system. We use the health system as independent variable and gestational age, weight and delivery type as independent variable. Results: The premature rate was significantly higher in public system (10.68% versus 5.32%) and the mean neonatal weight was lower (2383 g versus 2786 g). The mean weight of term newborn from the private system was lower than the public system (3326 g versus 3458 g). The cesarean rate in the private system was 81.1%; 55.4% were elective and 63.1% of them were performed between 37 and 38 weeks. Conclusion: The access of public patients to the private system looks like an advance to get equality in health, but that doesn't reflect in better perinatal result and in the cesarean rate.KEY WORDS: Health inequity, cesarean rate, public health system, private health system Trabajos Originales

Insulin, Cortisol, IGF, IGFBP-3 and Maternal Anthropometric Variables in Full Term Newborns Introduction: Fetal growth is a physiological phenomenon involving maternal, placentary and fetal factors. Objective: To analyze growth factors and maternal anthropometric variables in full-term newborns (NB) and compare them to their size. Patients and Methods: 138 newborns, 37-41 gestational weeks, sorted according to size in low, normal and large for gestational age. Umbilical cord blood was measured for: ELISA, insulin, cortisol, IGF, IGFBP-3. Results: A statistically significant difference was seen between maternal weight at the beginning and end of pregnancy, and BMI(body mass index) at the beginning of pregnancy with the size of the NB (p < 0.001). There was no significant difference between growth factors and NB size. Conclusion: Insulin, Cortisol, IGF1, IGFBP-3 do not show statistically significant differences with the size of a newborn, although the mean value of growth factors in normal and large NB for gestational age, were twice than mean values in low for gestational age newborns. There is a positive, statistically significant correlation between the size of the newborn, and the size of the mother, weight at the beginning and end of the pregnancy and the Body Mass Index of the mother at the beginning of the pregnancy.