According to Nancy Mohrbacher, IBCLC, FILCA, the answer is no. "It's totally normal — and expected — for your newborn to lose up to 10 percent of his birth weight in the first two days," she says. "Babies are born waterlogged (imagine taking a nine-month bath), and a good bit of what comes off is water weight. Plus, baby is adjusting to living without the constant stream of nutrition that he was receiving in your womb."
For the first few days, baby has been receiving your colostrum — super-healthy, nutrition-packed "first milk" that will protect him from illness and infection. "He'll only receive a few drops at a time, but that's all he needs," says Mohrbacher. "His little tummy is only the size of a marble, after all. The coming few days, your breasts will fill with mature milk, and baby will start packing on the pounds (okay, ounces). And he should be back up to birth weight within a couple of weeks."
"If baby is sucking at your breasts, pooping, peeing, and has lost less than 10 percent of his birth weight, there is no need to supplement with formula in these first days. In fact, doing so could keep your little one from taking enough colostrum, and introducing a bottle so early could make it more difficult to establish a good breastfeeding relationship."
"If your baby seems hungry, nurse more often. Newborns don't tend to get hungry at regular intervals; baby may need to feed as often as every half-hour at times, particularly at night. This doesn't mean he isn't getting enough or isn't breastfeeding correctly. It just means he's doing his job. If you are worried that baby isn't taking in enough (or any) milk at your breasts, have a lactation consultant or nurse help you make sure that you have a deep latch, and that there aren't any other issues preventing baby from sucking effectively."
When you should worry: if baby drops more than 10 percent of birth weight and/or if he isn't back up to birth weight by two weeks after delivery. If this is the case, talk to your pediatrician. Also, let a doctor know ASAP if baby isn’t dirtying diapers as he should.
This is the minimum number of bowel movements he should have each day:
DAY 1: One (black and gooey)
DAY 2: Two (black)
DAY 3: Three (black or greenish)
DAY 4: Three to four (greenish or yellowish)
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