Why Did My Newborn Change From Sleepy to Cranky?

My newborn was so sleepy right after birth, but is now super-cranky. What’s going on?
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By Bonnie Vengrow, Contributing Writer
Updated April 12, 2021
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Image: Kelly Huljev Photography

You’re not alone in wondering how that sleepy baby disappeared. A lot of new parents are surprised when their newborn trades in quiet time for tons of crying—usually some time around the third day of life.

Think about it this way: Baby just went through the biggest move of his or her life—from your warm and cozy uterus to a noisy, bright outside world. At the same time, you and your partner just became parents—and if you’re nursing, you’re trying to wrap your head around how to do it (not the easiest thing). Everything is new and different, and baby’s cryfests are the only way of communicating with you. Get to the bottom of what’s causing the tears.

“First, make sure there are no medical or health issues,” says Preeti Parikh, MD, a board-certified pediatrician, assistant clinical professor in the pediatrics department at the Mount Sinai School of Medicine, and an American Academy of Pediatrics fellow and spokeswoman. Look for fever (which is a temperature of 100.4°F or higher in a newborn), wet diapers (at least five to eight per day) and hunger. In the early days, baby may want to feed more often than you were mentally prepared for—at least every three to four hours (often more)—to prevent dehydration and regain his or her birth weight.

If baby’s health checks out, soothing can help quell the cries. Swaddling, turning on a white noise machine, or holding him or her tight and rocking or swinging can make baby feel that similar comfort he or she had in utero. If you’re breastfeeding, don’t offer a pacifier until baby’s one month old, says Parikh, since it could interfere with your developing nursing relationship.

So when does crankiness require a call to the pediatrician? Contact your doctor if: You see orange crystals or red tinges in the diaper (both are signs of dehydration); baby has greenish spit-up; poop with visible blood or mucus; is unusually sleepy and isn’t eating; skin or eyes look yellowish; has a fever; or is completely inconsolable.

Please note: The Bump and the materials and information it contains are not intended to, and do not constitute, medical or other health advice or diagnosis and should not be used as such. You should always consult with a qualified physician or health professional about your specific circumstances.

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