Continuous Glucose Profiles in Obese and Normal-Weight Pregnant Women on a Controlled Diet

Abstract

OBJECTIVEWe sought to define 24-h glycemia in normal-weight and obese pregnant women using continuous glucose monitoring (CGM) while they consumed a habitual and controlled diet both early and late in pregnancy.RESEARCH DESIGN AND METHODSGlycemia was prospectively measured in early (15.7 ± 2.0 weeks’ gestation) and late (27.7 ± 1.7 weeks’ gestation) pregnancy in normal-weight (n = 22) and obese (n = 16) pregnant women on an ad libitum and controlled diet. Fasting glucose, triglycerides (early pregnancy only), nonesterified fatty acids (FFAs), and insulin also were measured.RESULTSThe 24-h glucose area under the curve was higher in obese women than in normal-weight women both early and late in pregnancy despite controlled diets. Nearly all fasting and postprandial glycemic parameters were higher in the obese women later in pregnancy, as were fasting insulin, triglycerides, and FFAs. Infants born to obese mothers had greater adiposity. Maternal BMI (r = 0.54, P = 0.01), late average daytime glucose (r = 0.48, P < 0.05), and late fasting insulin (r = 0.49, P < 0.05) correlated with infant percentage body fat. However, early fasting triglycerides (r = 0.67, P < 0.001) and late fasting FFAs (r = 0.54, P < 0.01) were even stronger correlates.CONCLUSIONSThis is the first study to demonstrate that obese women without diabetes have higher daytime and nocturnal glucose profiles than normal-weight women despite a controlled diet both early and late in gestation. Body fat in infants, not birth weight, was related to maternal BMI, glucose, insulin, and FFAs, but triglycerides were the strongest predictor. These metabolic findings may explain higher rates of infant macrosomia in obese women, which might be targeted in trials to prevent excess fetal growth.

Normalizing Metabolism in Diabetic Pregnancy: Is It Time to Target Lipids?

“…Maternal obesity is associated with an increase in maternal lipid levels, higher triglycerides and VLDL (21), and lower HDL-C (21) than observed in lean women. Obese women without GDM have been shown to have higher glucose profiles on continuous glucose monitoring performed during pregnancy than normal-weight women; the mean time spent with glucose .6.7 mmol/L is longer in obese than normal-weight women (209 6 62 min vs. 33 6 12 min, P = 0.001) (22). In addition to changes in lipid and glucose metabolism, there is greater inflammation and more vascular endothelial dysfunction associated with obese pregnancy.…”

CGM, Pregnancy, and Remote Monitoring

“…Multiple indicators of glucose variability were higher, worse, and correlated more strongly with each other for women with T1D. 22 CGMs have been utilized in special situations in pregnancy, such as pregnancy after Roux-en-Y gastric bypass, 23 obese pregnancies, 24 masked (asymptomatic) hypoglycemia in insulin-treated GDM, 25 and exercise with T1D. 26 Three of the abovementioned studies showed more or similar rates of hypoglycemia among pregnancies with NGT compared with other groups.…”

Early nutrition programming of long-term health

“…As discussed earlier, this state of nutrient excess may be associated with a greater longterm risk for adult disease (50) . Maternal obesity and increased plasma lipid concentrations are related to fetal obesity, highlighting the importance of lipid status and potentially of placental fatty acid transfer (28,51,52) . While the maternal-to-fetal transfer of fatty acids, especially of PUFA, has been studied in normal pregnancies (53) , little is known whether and how this may be changed with maternal overnutrition/obesity or gestational diabetes.…”

“…Accelerated prenatal fetal growth can result from increased fuel supply to the fetus which occurs when maternal blood glucose and lipid levels are increased due to insulin resistance or gestational diabetes mellitus, both of which are prevalent among obese pregnant women. Indeed, maternal blood glucose and TAG concentrations are directly related to neonatal adiposity in obese women (28) . Better control of blood glucose levels, or reduction of insulin resistance during pregnancy through diet and exercise, offer ways of modifying fetal growth and potentially reducing the child's future risk of obesity (29) .…”