Objective. To determine what maternal risk factors that are present during pregnancy are associated with low birthweight (less than 2 500 g). Methods. A case-control study was conducted with 764 products of single births weighing less than 2 500 g at birth, and 1 437 controls from Hospital Gineco-Obstétrico Provincial in Sancti Spiritus, Cuba, during the 1997-2000 quadrennium. The data were obtained from clinical records, reports of labor, and personal interviews with mothers. A bivariate analysis was performed, and possible confounders were controlled for through dichotomous logistic regression using SPSS. A final multivariate statistical model used was to identify maternal risk factors for low birthweight. Results. The results of multivariate analysis showed a significant association between low birthweight, the presence of anemia when the pregnancy was detected, urinary tract infection during pregnancy, bronchial asthma, total maternal weight gain under 8 kg during pregnancy, smoking while pregnant, a history of previous children with low birthweight, arterial hypertension since before pregnancy, and inadequate timing of visit for follow-up of initial prenatal care. Conclusions. On the basis of these results it was concluded that, regardless of the impact measurement method used, it is important to try to reduce the risk factors identified in the study in order to lower the incidence of low birthweight in the province of Sancti Spiritus.

Objetivo. Identificar qué factores de riesgo materno durante el embarazo se asocian a la incidencia de bajo peso al nacer (menos de 2 500 g). Métodos. Se diseñó un estudio de casos y testigos con 764 casos de nacimiento simple con un peso al nacer de menos de 2 500 g, y 1 437 testigos del Hospital Gineco-Obstétrico Provincial de Sancti Spíritus, Cuba, durante el cuatrienio de 1997-2000. Los datos se obtuvieron de historias clínicas, registros de partos y entrevistas personales con las madres. Se realizó un análisis con dos variables y se controlaron los posibles factores de confusión mediante regresión logística dicotómica con el programa SPSS. Se usó un modelo final de múltiples variables para identificar los factores de riesgo maternos asociados con el bajo peso al nacer. Resultados. El análisis con múltiples variables mostró una asociación significativa del bajo peso al nacer con la presencia de anemia en la madre cuando se detectó el embarazo, la sepsis urinaria durante el embarazo, el asma bronquial, un aumento de peso materno menor de 8 kg durante todo el embarazo, el hábito de fumar durante el mismo, antecedentes de bajo peso al nacer en partos anteriores, la presencia de hipertensión arterial desde antes de la gestación y la consulta prenatal extemporánea. Conclusiones. A partir de estos resultados se concluyó que, independientemente de la medida de impacto utilizada, es importante tratar de disminuir los factores de riesgo identificados a fin de reducir la incidencia del bajo peso al nacer en la provincia de Sancti Spíritus.