Background: Low carbohydrate diets (LCD) have been recently prevalent in the medical and health field, especially in diabetes mellitus. We have applied LCD on thousands of patients with metabolic diseases and reported the clinical effect of LCD so far. Through our experience and research concerning LCD, the physiological role of glucose and ketone bodies during the pre- and post-partum period was investigated in this study. Subjects and methods: Subjects were 60 normal pregnant woman who had a normal delivery in full-term, without an abnormal glucose intolerance. Methods included the measurement of the value of ketone bodies in the umbilical cord blood, placental tissue fluid and maternal blood, associated with the value of blood glucose. As ketone bodies, the value of 3-hydroxybutyric acid (3-OHBA, beta-hydroxybutyric acid) was measured. 3-OHBA and glucose values were measured by the electrode method using Precision Exceed Kit (Abbott) and the conventional enzymatic cycling method, with comparison investigation of the data from two kits. Results: The average 3-OHBA levels were as follows: 2,235.0 μmol/L in the placenta, 779.2 μmol/L in the umbilical cord blood, in which the former is significantly higher than the latter (p < 0.001), 240.4μmol/L in the newborn after four days, and 366.7μmol/L after 30 days. The standard 3-OHBA level in a healthy man is less than 85 μmol/L. Glucose levels in the umbilical cord and placenta were 78.6 mg/dL vs 74.9 mg/dL, with no significant difference, and was the same as that of the pregnant woman. Accuracy management of the two kits revealed a significant correlation (r = 0.94, p < 0.001). 3-OHBA values of the maternal blood and umbilical cord blood were extremely elevated from the standard level, with a mutual significant correlation (r = 0.724, p < 0.001, n = 416). Conclusion: This clinical study concerning ketone bodies during pre- and post-partum period was investigated, and revealed that 1) a clinically rapid useful kit for ketone bodies had high reliability and validity compared with conventional kit, 2) elevated values of 3-OHBA were shown in the placental tissue fluid, umbilical cord, newborn and maternal blood, 3) 3-OHBA would be a physiologically indispensable element in nutrition metabolism for fetus and newborn at least until 30 days, with further development of investigation for ketone bodies.
