In some mothers, for no apparent reason, the production and the secretion of breast milk or colostrum could get delayed for even 3 - 4 days. However, during this time, mothers should place the baby's mouth against the nipple and try to feed every 2 to 3 hours as stimulation is the best method of initiating milk secretion.
However, it is good to inform one's doctor regarding not being able to feed as the doctor then can assess the baby for dehydration and recommend other means of giving a feed. However, as newborn babies require only very small amounts of colostrum in the beginning, one should not worry much.
At the same time, babies can lose about 7% of their birth weight in the first few days of life. This is normal and it not something to be alarmed about.
The advice would be to continue feeding the baby and in case the milk secretion does not start even after 3 - 4 days, further advice should be sorted from the doctor.