For centuries it has been considered that the due date for delivery in our species is 280 days after the onset of the last menstruation. However, in most cases this statement is not accurate. The main objective of this study was to determine the mean duration of pregnancy in our setting and whether it has experienced changes in recent years. A retrospective, population-based descriptive study was made of 102,169 deliveries assisted in Malaga University Hospital (Malaga, Andalusia, Spain) during the period 1998-2015. The mean gestational age at delivery was 269 days (SD 16 days), with a modal gestational age of 273 days. The mean duration of the singleton and multiple pregnancies was 271 days (SD 17 days) and 242 days (SD 20 days), respectively. A significant shortening of the duration of pregnancy was observed in the course of the study period.
Keywords: Andalusia; Naegelés rule; length of the pregnancy; post-term delivery; preterm delivery.