In this paper we present a fully automatic approach based on texture maps and optimal ellipse detection to segment and obtain measurements of the fetal head. The goals are to segment the fetal head and to measure the biparietal diameter (BPD) and head circumference (HC) using ultrasound images. By incorporating texture maps, morphological operations and active contours together with optimal ellipse detection, the segmentation and measurement of the fetal skull was performed. The results’ quality was evaluated by two obstetrician experts. A set of 10 studies was used to validate the segmentation process, obtaining a precision of 94.61%, a Dice similarity index of 97.19% and a maximum distance of 2.64 mm. To evaluate the head measures, a set of 23 images was used. The differences between experts and the proposed method are 2.72 mm for BPD and 2.73 mm for HC, with a correlation of 99.8% in both cases. These results suggest that the proposed method is suitable to be used for clinical applications in maternal medicine.