They baffle, surprise, and enchant us. Here's a guide to newborns.
mom burping newborn baby on her shoulder

Amazing Babies

From the moment they enter the world -- with their pickled skin, blinking eyes, and pay-attention-to-me cries -- babies mesmerize and mystify us. We watch, amazed, as they grow from helpless newborns, driven by instinct and reflexes, into determined toddlers with impressive wills and skills. This inevitable, incredible metamorphosis, both awesome and curious to witness, can have parents regularly scratching their heads and wondering, Is that normal? The answer, almost always, is yes. Listen in as three top pediatricians explain some of the puzzling things babies do.

Why Do Babies Look So Cute?

Scientists say that adults are evolutionarily programmed to find babies cute -- nature's way of ensuring that we care for them through sleepless nights and bouts of colic. But just what do we find so attractive? It's the eyes, mainly. Research has shown that adults prefer faces with larger eyes over faces with smaller eyes. And babies have disproportionately large eyes for their head: in fact, by 3 months, babies' eyes have reached their full adult width -- and may look huge until the rest of their features catch up. Other traits almost universally perceived as cute include a large, symmetrical head and a small nose and mouth. It's what makes us "ooh" and "aah" over all young creatures with improbably big peepers peering out from big round faces, whether they're puppies, kittens, or, especially, babies.

Why Do Babies Smile So Much?

Most parents won't witness their baby's first smile for 8 to 12 weeks. But usually by the third month, most babies will flash their first grin -- and melt their parents' hearts. These earliest smiles are probably unintentional facial movements, but our gushing responses to them virtually ensure we'll see more of the same. For the preverbal infant, smiling provides a means to communicate: when your baby smiles and you smile back, you're practicing the same type of back-and-forth exchange that happens later with language. From about 4 to 6 months, babies will smile at nearly everyone they encounter. But after that, many babies begin to develop stranger anxiety and will smile more discriminately, reserving their biggest crinkle-eyed, raised-cheek smiles for their parents and other loved ones, while greeting strangers with a more tentative, low-key smile, if any. But the wonderful thing about all babies' smiles -- big or small -- is that they're invariably genuine. Whereas adults may smile to be polite, when babies smile, they're happy.

An Eyes & Nose Thing

Why Do Babies' Eyes Change Color?

Eye color is determined by the amount of melanin, or pigment, in the iris; brown eyes have the most melanin, blue the least, explains Louis Borgenicht, MD, a Salt Lake City pediatrician and coauthor of The Baby Owner's Manual: Operating Instructions, Trouble-Shooting Tips, and Advice on First-Year Maintenance (Quirk Books). Most Caucasian babies are born with very little melanin in their irises and so have blue or gray eyes for their first six to nine months. But as babies' melanin gradually increases, their eyes may darken to green, hazel, or brown, usually arriving at their permanent color between 9 months and a year. African-American, Asian, and Hispanic babies typically arrive with brown eyes, since they have more melanin at birth.

Why Do Babies Sneeze So Much?

Newborns breathe exclusively through the nose for the first couple of months -- nature's way of making sure their mouth is free to suckle, explains Vincent Iannelli, MD, associate professor of pediatrics at the University of Texas Southwestern Medical Center. Consequently, their nasal passages must be kept clear, and that's where all that sneezing comes in. During the first days of life, babies sneeze to clear their lungs and nasal passages of residual amniotic fluid. After that, they sneeze to clear their nose of dust, or milk or formula. "And all babies sneeze in the winter, because the heat's on and the humidity is low," which can leave baby's nasal passages dry and irritated, notes Dr. Iannelli. While the sneezing can make your baby sound like she has a chronic cold, absent a runny nose or other symptoms it's just her body's way of ensuring she breathes easy.

Why Do Babies Cry Without Producing Tears?

Newborns have underdeveloped tear glands, which produce just enough tears to keep their eyes moist but not enough to spill over their lids when they're upset, explains Dr. Iannelli, who is also the author of The Everything Father's First Year Book (Adams Media). You won't see tears running down the cheeks of most infants until they're about 7 or 8 months old, he adds. The exception: babies with a blocked tear duct will regularly shed tears from the affected eye, even when they're not crying, starting as early as 2 or 3 weeks of age. Blocked tear ducts, which prevent the normal nasal drainage of tears, are relatively common -- some 5 percent of babies are born with at least one -- but more than 90 percent unclog spontaneously within the first year. You may be able to move things along by massaging the tear ducts -- ask your doctor how to do it. In some cases, the tear ducts may need to be opened with a tiny probe, a simple surgical procedure performed by ophthalmologists.

Drool, Spit, and More

Why Do Babies Hiccup So Much?

Infants are prone to hiccups because of a common and temporary malfunction of their diaphragm, explains Dr. Borgenicht. The diaphragm is that large muscle that sits between your chest and abdomen. Normally, it expands on the inhale and contracts on the exhale, but in some newborns, just the opposite happens -- the diaphragm contracts as they breathe in and expands as they breathe out, a glitch that can trigger hiccups but is otherwise harmless. As babies mature physiologically, hiccupping episodes become less frequent. If baby seems bothered by her hiccups, says Dr. Borgenicht, you can try stopping them by blowing on her face or taking her out into the cold air; either may cause her to gasp, and the sudden inhale may correct the movement of her diaphragm. Feeding baby may also reset the diaphragm.

Why Do Babies Drool?

Though it's commonly blamed on teething, drooling usually starts around the second month, a good five months or more before most babies cut their first tooth, notes Jennifer Shu, MD, coauthor of Heading Home with Your Newborn: From Birth to Reality (American Academy of Pediatrics). This increased saliva production has less to do with baby's teeth than with what he'll soon be chewing. The drool dripping down his chin is full of digestive enzymes, which will help break down the solid foods he'll start eating between 4 and 6 months. Incidentally, babies don't produce more saliva than adults. But they tend to let the saliva run out rather than swallow it, observes Dr. Shu. This is especially true when baby is teething -- and gnawing on things to relieve the pressure in his gums -- which may be why we link the two.

Why Do Babies Spit Up So Much?

In many babies, the esophagus is a two-way street, at least for the first few months, until the sphincter muscle at the top of the stomach strengthens sufficiently to keep food down, explains Dr. Shu. Picture your baby's stomach as a water balloon with the top untied, she suggests. If you fill it up and then lay baby down or squeeze him, or if an air bubble gets caught beneath the milk or formula and rises up, some liquid is bound to come out, says Dr. Shu. To minimize spit-up, hold baby at an upright angle, with his head higher than his stomach, during feedings and for about 20 minutes after, she recommends.

The good news is that most babies stop spitting up (or do it a lot less) as their stomach muscles tighten, they spend more time sitting up, and they begin to eat solid foods. In the meantime, as long as baby continues to gain weight and seems generally content, there's no need to worry, even if he returns a portion of most or all meals. If, however, your baby spits up frequently, and is failing to gain weight or seems to be in pain or distressed following feedings, he may have acid reflux; talk to your pediatrician, who may prescribe an acid-reducing medication. But in most cases, assures Dr. Shu, spitting up is a laundry problem, not a medical one.

Hair and Skin Issues

Why Do Babies Lose their Hair?

Most babies shed the hair they are born with in the first six months of life. This type of near-total hair loss, called telogen effluvium, is triggered by the drop in maternal hormones in baby's body in the weeks and months following birth. (Hormonal shifts may similarly cause moms to shed excess hair postpartum -- a temporary loss that's usually restored within a year.) The hair that grows back on baby's head may differ in color and texture from the crop she arrived with (so don't get attached to those golden ringlets or jet-black spikes just yet!). Babies may lose hair in patches as well, if, for example, their head repeatedly rubs in the same spot against the crib mattress. "Tight barrettes or headbands can also cause this sort of hair loss," says Dr. Shu.

Why Do Some Babies Get Acne?

Maternal hormones lingering in baby's body for the first few months after birth are the culprit, says Dr. Shu. Some 20 percent of babies develop acne -- with red pimples or whiteheads erupting on their cheeks, forehead, or chin -- at around 3 to 4 weeks. Fortunately, most babies' skin will clear by about the fourth month, requiring only gentle cleansing with plain water or a mild baby wash, says Dr. Shu. Avoid vigorous scrubbing, as well as lotions and perfumed soaps, which may make acne worse. In severe cases, doctors may recommend an over-the-counter or prescription medication, or an antibiotic if pimples become infected. But typically the acne will disappear as Mom's hormones leave baby's system.

Fascinating Baby Behaviors

Why Do Babies Love Mirrors?

Do they know they're seeing themselves? When babies look in the mirror, initially they're unaware that the face in the glass is theirs, but they're still captivated. Babies are inherently interested in human faces -- and seem particularly drawn to those that are close in size to their own, says Dr. Shu. Studies suggest babies begin to recognize themselves about midway through their second year. In one famous British experiment, researchers asked mothers to play with their babies, age 9 to 24 months, in front of a mirror. The mothers then pretended to wipe dirt off their child's face but instead dabbed rouge on their nose. The babies younger than 15 months made no attempt to touch their own red nose (though some swatted at their nose's reflection), while nearly all of those 21 months and older touched the rouge.

Why Do Babies Love to Be Rocked?

Most babies love to be rocked, swayed, and danced in circles -- in a way that would make many adults motion sick! Like their fondness for white noise, this could be a holdover from the days in utero, suggests Dr. Shu, where for nine months babies float in a fluid environment. "Think of how weird it feels after you've been on a boat and you step off onto solid ground," she says, adding it may feel similarly strange for infants who find themselves suddenly lying in a static bassinet. Rocking or swaying while holding your baby may bring back for her the comforting rhythm of the womb.

Why Do Some Babies Bang Their Head?

While this behavior is understandably disconcerting for parents, some 20 percent of babies and toddlers bang their head. For reasons unknown, it's three times more common in boys than girls. Some babies may bang their head out of frustration and an inability to express themselves, says Dr. Shu. For these children, it may help to try to put their emotions into words for them: "I know you're mad because you want that cookie now and don't want to wait until after dinner." Hearing that you understand may defuse the tantrum, suggests Dr. Shu.

Other babies seem to do this as a self-soothing technique, rhythmically rocking and banging as they try to calm down or fall asleep. They may do it more frequently when they're teething or have an ear infection, notes Dr. Shu, perhaps to distract themselves from their discomfort. Still others may bang their head to elicit a reaction. "It gets them attention, even if it's not good attention," says Dr. Shu. For this reason, it's usually best to ignore head-banging, since any response will only reinforce the behavior, she says. Just be sure your child is in a safe place where he can't bang his head against sharp, breakable, or unstable surfaces. Though head-banging looks dangerous, your baby generally won't knock his noggin hard enough to hurt himself, assures Dr. Shu.

Why Party All Night and Sleep All Day?

The most common theory is that this pattern is established in the womb, when Mom's daytime comings and goings rocked and lulled baby to sleep, leaving him plenty of energy for midnight somersaulting. This routine may continue after birth, with baby catching plenty of shut-eye in the car or stroller, then clamoring for playtime at 2 a.m. Since your baby has no inherent way of discerning day from night, provide plenty of cues, says Dr. Borgenicht. When the sun's up, open the shades, turn on the lights and music, and try to keep baby actively engaged for substantial stretches of time, he advises. In the evening, dim the lights and limit stimulating sights and sounds. During middle-of-the-night feedings and diaper changes, keep the room dark and the chatter to a minimum. If you're consistent, your baby will soon get the message that daytime is for playing and nighttime is for sleeping, says Dr. Borgenicht.

Originally published in American Baby magazine, December 2006.

All content here, including advice from doctors and other health professionals, should be considered as opinion only. Always seek the direct advice of your own doctor in connection with any questions or issues you may have regarding your own health or the health of others.

American Baby