Ultrasonographic assessment of fetal and neonatal spleen

To assess the growth and function of the fetal spleen, ultrasonographic examinations were performed on 229 normal fetuses, ranging from 20 to 41 weeks, menstrual age. Curvilinear relationships were found between the menstrual age and splenic length (R2 = 92.7%), circumference (R2 = 93.9%), and area (R2 = 95.2%). A normal range of splenic length, circumference, and area measurements for estimating the growth of the fetal spleen during normal pregnancy was generated. Splenic parameter values just after delivery were significantly lower than those measured within 7 days before delivery, and returned to former sizes 24 hours later, in both vaginal delivery and cesarean section groups. Splenic parameter values in the vaginal delivery group were also significantly lower than those in the cesarean section group, just after delivery. Moreover, neonatal splenic length showed negative correlations with lactate dehydrogenase (p < 0.001) and glutamic oxaloacetic transaminase (p < 0.05) in the umbilical venous blood, respectively. These results provide a foundation for the evaluation of fetal splenic growth and function during pregnancy and the early neonatal period.