The possibility that it can be absorbed a certain amount of salicylate does preferable to resort to an alternative drug. Some observations suggest, however, that the total absorption of salicylate is equal to or less than 1% of the dose given to the mother.
There are reports of metabolic acidosis in neonates whose mothers received doses higher than 3.5 gr. of aspirin per day
Warning of the manufacturer:
This medication should not be used during lactation unless clearly necessary.