There’s no sweeter sight than a sleeping baby, but getting your baby to bed can turn into a daily struggle.

If you're a sleep-deprived new parent looking for help, you might want to try pediatrician Harvey Karp's method for soothing crying or fussy infants and getting them to sleep. At the heart of his method are the so-called five S's: swaddle, side or stomach position, shush, swing, and suck.

Sound intriguing? Read on.

The "Happiest Baby" method

Harvey Karp says the best way to calm your newborn and get him to sleep is by re-creating the noises, movement, and snug environment of the womb. And the "five S's" baby sleep strategy outlined in Karp's bestselling book, The Happiest Baby on the Block, is designed to do just that.

Karp, an assistant professor of pediatrics at the University of Southern California School of Medicine, describes the first few months after birth as the "fourth trimester." Babies are out of the womb, he says – but they're really not ready for our world.

Human babies need special care because they're immature at birth compared with the babies of most other mammals. To offer just one example: A newborn horse can walk, while humans take months to get mobile.

"Our newborns are smushy little creatures who must be 'evicted' from the womb three months before they’re ready so their big heads don’t get stuck in the birth canal," he says. We assume that newborns need calm and quiet, but the place from which they've just emerged is quite an active and noisy place.

Babies in utero are rocked and swayed. They're bombarded with the whooshing and gurgling sounds of their mother's body and cradled by the walls of their "room." No wonder, Karp says, they feel insecure and unhappy when lying alone in a quiet nursery, their arms and legs loose and flailing.

"Most babies doze much better when surrounded by some of the soothing sensations they enjoyed in the womb. These sensations work so well because they turn on a calming reflex – an off-switch for crying and on-switch for sleep that all babies are born with."

The five S's: Swaddle (#1)

What it is
Wrap your crying or fussy baby snugly, arms at her sides, in a thin blanket. Babies can also be swaddled with their arms loose, but Karp strongly recommends wrapping your baby's arms inside the blanket.

Why it works
Swaddling soothes babies by providing the secure feeling they enjoyed before birth. After months in that confining environment, Karp says, "the world is too big for them! That's why they love to be cuddled in our arms and to be swaddled."  

Done as Karp recommends, swaddling keeps your baby's arms from flailing and prevents startling, which can start the cycle of fussing and crying all over again. It also lets your baby know that it's time to sleep.

Swaddling helps babies respond better to the other four "S's," too.

How to do it
Karp recommends swaddling your baby for sleep every time, whether it's a morning nap or going down for the night. Always lay your baby down to sleep on her back – never on her side or tummy. To avoid overheating, use a thin blanket and make sure the room isn't too warm.

Swaddling is not hard to do, but you do need to learn the proper technique to make sure swaddling will be safe and effective. The idea is to wrap babies snugly so they won't try to wiggle out of the swaddle, but leave enough room at the bottom of the blanket for them to bend their legs up and out from their body. (Swaddling the legs straight can lead to hip problems.)

For more swaddling guidance, watch a quick demo of the art of swaddling, see a how-to-swaddle slideshow, or read our article. You'll be an expert in no time!

Video: 3 simple swaddling techniques

Slideshow: How to settle your baby with a snug swaddle

Article: What it means to swaddle your baby

You can also search for Harvey Karp's Happiest Baby videos online or watch his DVDs to learn how to swaddle.

Do swaddle your baby for naps, for the night, and when she's crying. Don't swaddle when she's awake and happy. Karp says most babies can be weaned off swaddling after four or five months.

Swaddling alone usually isn't enough to do the trick. For more help, move on to "S" number 2: the side or stomach position.

The five S's: Side or stomach position (#2)

What it is
Now that you've swaddled your baby, you can begin to calm your crying or fussy baby by putting him on his side or stomach.

Why it works
To reduce the risk of SIDS, experts recommend putting babies to sleep on their back. But because newborns feel more secure and content on their side or tummy, those are great positions for soothing (not sleeping).

How to do it
Hold your fussing or crying baby in your arms in a side or tummy-down position in your arms, on your lap, or place him over your shoulder. Use this "S" only for soothing your infant. Never put him on his side or stomach when he's asleep. Once he falls asleep, put him on his back.

Sometimes swaddling and being held in a side or stomach position is enough – but if not, add "S" #3: shush.

The five S's: Shush (#3)

What it is
A sound that calms and comforts your baby, helps stop crying and fussing, and helps your baby go to sleep and stay asleep.

Why it works
Newborns don't need silence. In fact, having just spent months in utero – where Mom's blood flow makes a shushing sound louder than a vacuum cleaner – they're happier, they're able to calm down, and they sleep better in a noisy environment. Not all noises are alike, however.

How to do it
At its simplest, you apply the "shush" step by loudly saying "shhh" into your swaddled baby's ear as you hold her on her side or tummy. Put your lips right next to your baby's ear and "shhh" loudly (usually while gently jiggling her – see "S" #4).

Shush as loudly as your baby is crying. As she calms down, lower the volume of your shushing to match.

In addition, Karp recommends play a recording of white noise while your baby sleeps. Some sounds are much more effective than others, however. He says that fans, sound machines, and recordings of ocean waves may not work, and recommends sounds that are more low and "rumbly" (like the sounds in the womb) such as those on his own Super-Soothing Calming Sounds CD. You can experiment and see what helps your baby.

Play the sounds as loud as your baby is crying to calm her down. To accompany sleep, play them as loud as a shower. 

As your baby gets older, you can continue to use a CD of white noise for many months to come. "Sound is like a comforting teddy bear. Play it for all naps/nights for at least the first year," Karp says.

Holding your swaddled but fussy baby in a side or stomach position and shushing in her ear may be all your baby needs to calm down. But if not, you can add "S" #4: swing.

The five S's: Swing (#4)

What it is
A baby swing might be your first thought, but that's not what "swing" is about. Instead it refers to jiggling your swaddled baby using very small, rapid movements.

Why it works
In utero your baby was often rocked, jiggled, in motion. That makes "S" #4 familiar and comforting. In combination with the first three S's, it can do wonders when a baby is upset.

How to do it
Do this while shushing (or playing white noise to) your swaddled baby in a side or stomach position. Be sure to support your newborn's head and gently jiggle – do not shake – your baby. Karp describes it as more of a "shiver" than a shake, moving back and forth no more than an inch in any direction.

"My patients call this the 'Jell-o head' jiggle," he says.

In Karp's opinion, other types of movement (being rocked in a rocking chair, swung in a baby swing, or carried in a sling, for example) are useful for calm babies, but this gentle jiggling is more effective for a wailing baby.

There's one more "S" in Karp's system, "S" #5: suck. Add #5 as needed.

The five S's: Suck (#5)

What it is
This simply means giving your baby a pacifier or thumb to suck on.

Why it works
Some babies love to suck and find great comfort in it. If your baby is in that camp, sucking may help her relax and calm down.

How to do it
Give your swaddled baby a pacifier or your thumb if she's upset and seems to want to suck. In combination with being held on her side or tummy, being soothed with loud shushing or white noise, and being gently jiggled, sucking may do the trick.

Pacifiers reduce the risk of SIDS, so it's okay to let your baby keep the pacifier in bed.

More about Harvey Karp's five S's

The five S's only work when they're done exactly right, Karp says. He compares babies' calming reflex to the knee reflex that doctors test with a little hammer: It only works when the knee is hit in exactly the right spot. If it's hit an inch too high or low, there's no response.

If you do all five correctly, Karp says, his technique works for 98 percent of babies. (He recommends that the other 2 percent talk to their doctor.)

This doesn't mean you need to follow all five S's. Some babies need only swaddling and being held on their side or stomach, for example. Every baby is different, so experiment and see what works for your child.

Keep in mind that Karp's method is aimed at babies during their first four months of life. As he puts it, "After 4 months, the five S's may still work (even adults fall asleep rocking in a hammock and to the sound of rain), but the magic is no longer irresistible (shushing an irate 8-month-old might make her even madder!)."

Baby sleep tips from Harvey Karp

Your baby is lying calmly in your arms. But when you put him down in the crib or bassinet, he cries. Or you've nursed your baby and she's fallen asleep in your arms, but when you put her down, she's awake and tearful. How do you get your baby to go to sleep – and stay asleep?

Karp says, "It's fine to let your baby fall asleep on your chest – in fact, it's almost impossible to prevent it."

And then he makes a surprising suggestion: Once your baby is 6 weeks old, he says, try waking your baby with a gentle jostle until her eyes open and then setting her down. If your baby is unswaddled, Karp recommends gently waking her, swaddling her, and laying her back down. He calls this technique "wake and sleep."

Waking a sleeping child sounds like a bad idea. But Karp views it as a good thing – an opportunity for your baby to start learning in his first weeks and months how to put himself to sleep. And of course, if you're following the five S's, your new baby is swaddled and he's going to sleep to the tune of some suitably rumbly white noise.

Every one of the five S's is a cue for a tired baby. Each cue says, "It's time to sleep," in the same way that a pillow and a dark room tell a weary adult brain to go into sleep mode.