Glucose supply in postpartum dairy cows may impinge upon early pregnancy by affecting maternal and placental endocrinology as well as substrate availability to the developing conceptus. The objective was to test the effect of glucose infusion from d 32 to 45 of pregnancy on plasma hormones and metabolites, milk production and conceptus growth. Dairy cows (n = 10) were assigned to glucose (GLUC; n = 5) or saline (SAL; n = 5)]. The GLUC cows received 750 g of glucose per d via continuous intravenous infusion of 40% dextrose (0.52 g glucose/min). The SAL cows were infused with an equal volume of 0.9% saline. Infusions began on d 32 of pregnancy (98 ± 15 d postpartum) and ended on d 45 of pregnancy. Blood was collected twice daily during the infusion. Fetal and amniotic vesicle length and width were measured on d 31 (1 d before infusion) and d 33, 35, 37, 39, 41, 43 and 45. Data were analyzed by using PROC MIXED of SAS. Compared with SAL, the GLUC cows had greater blood glucose (81.7 ± 2.1 vs. 74.2 ± 2.1 mg/dL; P < 0.05). Plasma progesterone (P4; 9.5 ± 1.3 vs. 9.5 ± 1.3 ng/mL), insulin (7.7 ± 1.7 vs. 7.0 ± 1.7 ng/mL), IGF1 (159 ± 27 vs. 143 ± 27 ng/mL), β hydroxybutyrate (0.93 ± 0.08 vs. 1.02 ± 0.08 mM), nonesterified fatty acids (280 ± 10 vs. 264 ± 10 µEq/L) and pregnancy-associated glycoproteins (PAG; 64 ± 21 vs. 73.2 ± 21% of assay control) were not affected (P > 0.10; GLUC vs. SAL). There was no effect of treatment on milk yield (26.8 ± 2.4 vs. 24.6 ± 2.2 kg/d; GLUC vs. SAL) or as-fed consumption of total mixed ration (63 ± 4 vs. 67 ± 3 kg/d; GLUC vs. SAL). There was an effect of day of pregnancy (P < 0.001) but no effect of treatment on length, width, or volume of the fetus or amniotic vesicle. All hormone and metabolic data were provided as independent variables to explain variation in conceptus measurements using backward elimination (GLMSELECT of SAS). The only significant effects remaining were day (P < 0.001) and plasma progesterone (P4; P < 0.001; positive association for P4 with all conceptus measurements). Glucose infusion from d 32 to 45 of pregnancy increased plasma glucose but did not affect growth of the conceptus. Greater plasma P4 was associated with larger conceptuses.