Body composition and energy metabolism in normotensive and hypertensive pregnancy.

OBJECTIVE: To determine whether the insulin resistance syndrome and altered body composition are features of hypertensive pregnancy.
DESIGN: Women were recruited in the third trimester of pregnancy from the antenatal clinic, day assessment unit, and maternity ward of St George Hospital, Sydney. POPULATION: Women with pre-eclampsia (n = 12), gestational hypertension (n = 12), essential hypertension in pregnancy (n = 11), and normotensive pregnancy (n = 10).
METHODS: Energy metabolism was assessed by indirect calorimetry to measure basal metabolic rate and diet-induced thermogenesis. Body composition was measured as lean body mass, total body water and fat mass by bio-electrical impedance. Blood was collected for measurement of glucose, insulin and lipid profiles. Insulin resistance was indirectly assessed by the insulin and glucose concentrations and diet-induced thermogenesis.
RESULTS: Women with essential hypertension and gestational hypertension were heavier than women with normotensive pregnancies both pre-pregnancy and in the third trimester, whereas women with pre-eclampsia were similar to those with normotensive pregnancy. Women with essential hypertension were otherwise similar to normotensive pregnancy but women with gestational hypertension had a reduced diet-induced thermogenesis and almost double insulin levels. Women with pre-eclampsia had a similar body composition and insulin levels but reduced basal metabolic rate, diet-induced thermogenesis and glucose levels compared with normotensive pregnancy.
CONCLUSIONS: Women who develop gestational hypertension, but not pre-eclampsia, are more likely to be overweight. Women with essential hypertension are similar to women with normotensive pregnancy throughout pregnancy. Both gestational hypertension and pre-eclampsia appear to be associated with some degree of insulin resistance, greater than that occurring in normal pregnancy.