Not necessarily. If your baby is breastfeeding at least 8-12 times a day and is having the appropriate number of wet diapers and bowel movements, supplementation in the first few days is not necessary and can be harmful to baby’s health and to your milk supply.
Day 1–1 bowel movement and 1 wet diaper
Day 2–3 bowel movements and 2 wet diapers
Day 3–3 bowel movements and 3 wet diapers
Day 4 3-4 bowel movements (changing to green/yellow) 6 wet diapers
Day 5 3-5 yellow bowel movements the size of an American quarter and 6 wet diapers
Some babies lose excessive amounts of weight in the first day after birth if their mothers were given IV fluids during labor. See:
An observational study of associations among maternal fluids during parturition, neonatal output, and breastfed newborn weight loss; Joy Noel-Weiss1*, A Kirsten Woodend2, Wendy E Peterson1, William Gibb3 and Dianne L Groll4 http://www.internationalbreastfeedingjournal.com/content/6/1/9/abstract
A baby who is feeding well will have moist mucous membranes, should wake to feed for at least some of the feeds, and have some alert times during the day or night. Your baby should begin gaining 2/3-1 ounce a day by day 5 or 6. If baby is not gaining at this point see: http://feedthebabyllc.comcare-plan-for-milk-supply/
If baby has jaundice, keep in contact with baby’s health care provider.