Effect of methylxanthines on lactational performance of rats.

Caffeine, theophylline and theobromine are commonly consumed methylxanthines. There are conflicting reports that methylxanthines may adversely affect the outcome of pregnancy. The effects of methylxanthines on lactational performance were investigated by administration of pure alkaloids via drinking water to Wistar albino rats throughout pregnancy and lactation. Litter growth was used as an index of lactational performance in relation to maternal food and fluid intake, changes in weight, and lipid content of the carcass. Caffeine induced increased fluid intake (p less than 0.01). While theophylline produced no significant differences in litter growth, maternal weight and carcass fat during pregnancy/lactation compared with controls, caffeine and theobromine significantly enhanced litter growth (p less than 0.05 and 0.01, respectively). The enhancement in pup growth did not involve increases in maternal food intake or maternal lipid mobilization.