Prealbumin is widely used for nutritional monitoring of hospitalized patients since it is relatively unaffected by non-nutritional factors. This prospective study examined the influence of pregnancy on PA among 10 Pregnant (Preg) and 20 Non-pregnant (N-preg) women receiving care at a Medical Center. Measurements were taken at 5-7 weeks gestation (WG) , 15-18 WG, 28-32 WG, during labor, 24 hours post-partum (PP), 2 weeks PP, and 6 weeks PP. Repeated measure ANOVA showed significant change in the Preg cohort for: Hematocrit (HCT) over time (P=<0.000); Body Mass Index (BMI) over time (P=<0.01); and PA during the Preg vs N-preg time period(P=<0.00001), with Preg time period being significantly lower than N-preg. In the N-preg cohort, PA did not change over a corresponding 6 month time period. HCT, Preg time period, and BMI were found to influence PA in a step wise regression of the Preg cohort. HCT accounted for 25% (P=<0.000001)-and the Preg time period an additional 3% (P=<0.00001)-of the decrease seen in pregnancy. Estimated energy-needs-met and estimated protein-needs-met in this healthy, well nourished population was not associated with variation in PA in either cohort.