Longitudinal changes in the continuous glucose profile measured by the CGMS® in healthy pregnant women and determination of cut-off values

Objective: This longitudinal study performed continuous evaluation of daily blood glucose level profiles in healthy normal-weight pregnant patients during various gestational age and determined normal levels. Study design: Thirty-two healthy normal-weight pregnant women received a continuous glucose monitoring system (CGMS (R)) device for periods of 72 h in the 16th, 22nd, 30th and 36th weeks of gestational age and at 6 weeks after delivery. All observations took place in the outpatient clinic of the Charite hospital. The daily blood glucose level profiles obtained with the CGMS provided pre- and postprandial blood glucose levels and a mean glucose value for a 24-h period. Caloric intake was determined using detailed food logs. Additionally, a fetal biometry and an measurement of maternal weight were performed at each visit. The correlation was tested using Spearman's test. Results: The average age of the study subjects was 29.6 +/- 4.5. Average pre-pregnancy BMI was 22.4 +/- 2.5 kg/M2. The births occurred on average in the 40th week of pregnancy. Average caloric intake was 2223 +/- 356 kcal. No significant changes in caloric intake were observed during the course of the study. The blood glucose levels showed a significant rise throughout the course of the pregnancy, going from 4.84 +/- 0.4 mmolA (87.2 +/- 7.2 mg/dl) during the 30th week of pregnancy to 5.22 +/- 0.5 mmolA (94.0 +/- 9.0 mg/dl) during the 36th week (p = 0.002). Postpartum levels were 5.20 +/- 0.5 mmolA (93.7 +/- 9.0 mg/dl) (p = 0.51). Fasting blood glucose levels did not change during the course of the pregnancy. A noticeable aspect were the significantly increased fasting postpartum levels with 5.02 +/- 0.6 mmol/l (90.4 +/- 10.8 mg/dl) (p = 0.00). Analysis of the postprandial glucose levels confirmed a rise from 5.30 +/- 0.6 mmol/l (95.5 +/- 10.8 mg/dl) in the 16th week to 6.14 +/- 0.7 mmol/l (110.6 +/- 12.6 mg/dl) in the fourth study phase (36th week), and a decrease after the birth to 5.59 +/- 0.6 mmol/l (100.7 +/- 10.8 mg/dl). These measurements were adapted to the gestational age. Conclusion: Continuous measured glucose levels rose during the pregnancy in healthy pregnant women in spite of normal pre-pregnancy metabolism and unchanged carbohydrate intake during gestation. These results suggest the necessity of gestational-age-dependent cut-off values. (C) 2008 Elsevier Ireland Ltd. All rights reserved.