Observational studies on the association between birth weight and adult blood pressure provide suggestive evidence that exposures during fetal development can have lasting impacts on health. The effect of maternal nutrition during pregnancy on offspring blood pressure has been demonstrated in animal models, but data from cohort studies in humans have proven inconclusive. The follow-up of randomised controlled trials of nutritional supplementation during pregnancy can add high quality data to this research field; this thesis focuses on the effects in three separate trials. Protein energy supplementation provided to pregnant women in rural Gambia was unrelated to offspring blood pressure at 11-17 years old (n=1267). Again in The Gambia, maternal calcium supplementation compared to placebo was also unrelated to offspring blood pressure at 5-10 years old (n=350). In rural Bangladesh there was no effect of maternal food or multiple micronutrient supplementation on offspring systolic blood pressure at 4.5 years old (n=2335). The micronutrient intervention was also unrelated to offspring diastolic blood pressure, but there was evidence that an early invitation to enter a governmental food supplementation programme was associated with marginally lower diastolic blood pressure: 0.58mmHg (95% Cl: 0.06,1.11; P: 0.03). In this setting, randomisation to receive counselling to promote exclusive breast feeding was not associated with offspring blood pressure at 4.5 years of age and none of the interventions were associated with offspring kidney function, assessed as ultrasound-obtained volume and glomerular filtration rate calculated from plasma Cystatin C. These data suggest that the maternal diet during pregnancy, at least those aspects of intake that can be altered during supplementation trials, may not be directly relevant for the determination of offspring blood pressure. Nutritional exposures during other stages of the life course may prove to be more important