Placental glucose transport and utilisation is altered at term in insulin-treated, gestational-diabetic patients

Aims/hypothesis. We have previously shown that placentae from patients with gestational diabetes mellitus who did not receive insulin had lower glucos e transport and utilisation than non-diabetic control subjects. To assess t he placental glucose handling characteristics of women with gestational dia betes mellitus receiving insulin, we examined glucose transport and utilisa tion in placentae from three groups of women after term delivery: those wit h gestational diabetes mellitus and receiving insulin (n = 9, insulin group ); those with gestational diabetes mellitus and not receiving insulin (n = 10, no insulin group); and those with normal, non-diabetic pregnancies (n = 9, control group). Methods. Dual perfusion of an isolated placental lobule was done using maternal glucose concentrations of 4, 8, 16 and 24 mmol/l. Glucose and L-lactate concentrations in the maternal and fetal effluents we re measured. Direct glucose transfer from the maternal to the fetal effluen t was measured using C-14-(D)-glucose. Mean rates in mu mol ming(-1) (wet t issue) at maternal glucose concentration of 8 mmol/l are shown. Results. Gl ucose uptake from the maternal perfusate (insulin group 0.57, no insulin gr oup 0.30) and net glucose transfer to the fetal effluent (insulin group 0.4 1, no insulin group 0.20) both increased in the placentae of women receivin g insulin compared with the diabetic group not receiving insulin. Both grou ps of patients had lower placental glucose utilisation than the control gro up (insulin group 0.16, no insulin group 0.10, control group 0.25). Conclus ion/interpretation. These results suggest that materno-fetal glucose transp ort increases in the placentae of women with gestational diabetes mellitus who receive insulin compared with those women who do not receive insulin.