The day of Mia's birth was magical for her parents and other loved ones, but her response was to go into a state of deep sleep -- a self-preservation mechanism that helps babies turn off all the new stimulation, mentally check out, and sleep off the stress of being born.

This response is echoed in all human newborns, according to an infant sleep study focusing on the first day of postnatal life that was published in the journal Pediatrics in 1993. But when they wake up from that initial deep sleep, newborns can be easily startled and need help to calm or soothe themselves back to sleep in their strange new surroundings.

Not quite ready for the world

"When babies are first born, they don't have the brain maturity to deal with the outside world," says Jennifer McArthur, co-director of the Northwest Association for Postpartum Support. "They depend on their parents for basic survival, but also for soothing, because they just don't know how to soothe themselves until they are about 4 months old."

Compared with other mammals, human infants are much more fragile and vulnerable at birth. They need constant attention and physical contact with other human beings. At the time of birth, they are unable to lift their head, move about, keep themselves warm or feed themselves -- unlike many other baby animals that are born with survival instincts that allow them to get up and walk or run as soon as they are born.

Experts say human babies are born with just three basic reflexes: sucking, swallowing and breathing -- and even breathing can be irregular. This may have to do with the immaturity of the human newborn's brain, which is only about 25 percent of its adult weight at birth, while most other mammals are born having 60 percent to 90 percent of their adult brain size.

James McKenna, Ph.D., professor of anthropology at Notre Dame University, has researched the connection between babies' brain maturity at birth and our species' anthropological construction. In a 1994 article in the journal Children's Environments, McKenna explains that when primitive women evolved to stand up on two legs, the shape of the female pelvis became narrower and resulted in human babies being born three to four months earlier, before their heads grew too large to pass safely through the birth canal.

For this reason, some experts say human babies need the first three months of life to give their brain and central nervous system the time needed to mature. In the course of those three months, an infant develops into a baby who is able to respond to the outside world. Breathing starts to regulate. She becomes able to lift her head, smile, coo, develop social interactions, and begin to soothe herself. This time between birth and the end of a baby's third month is a unique stage of life that many now refer to as the "fourth trimester."

The "5 S's"

Although mothers have known much of this instinctively for centuries, the concept of the fourth trimester has been popularized by Harvey Karp, M.D., assistant professor of pediatrics at UCLA and author of The Happiest Baby on the Block.

Karp began studying colic and newborn crying in the early 1980s. He discovered that colic is basically nonexistent in several cultures around the world. "I studied the Kung San tribe of South Africa and discovered that their babies very rarely cry. Mothers soothe and calm their babies very quickly. They carry them all day long while walking miles a day," says Karp. "They also nurse their babies 50 to 100 times a day, and sleep with their baby on top of them."

Karp says the American approach of having a newborn sleep in a separate room from his parents, who then tiptoe around trying not to disturb him, does not work well for babies. Instead, based on his research, Karp has developed a method that he says can reduce, if not eliminate, crying and colic symptoms in young babies.

"All infants are born with an 'off' switch for crying," Karp explains. "Inside the uterus they get constant holding and rocking, and the noise in there actually is louder than a vacuum cleaner. Then suddenly they are born and it's quiet and still. So the best way to activate a baby's calming reflex is to emulate the movements and noises that babies experience inside the uterus. But you have to do it exactly right."

In his book, and the corresponding DVD, Karp teaches parents techniques to help re-create the womb experience. Karp calls the techniques the "5 S's" and they consist of:

• Swaddling -- Tight swaddling provides the continuous touching and support the fetus experienced while still in the womb.
• Side or stomach position -- Karp recommends placing a baby on her left side to help with digestion, or on her stomach to provide reassuring support. Once the baby is sleeping peacefully, you can turn her onto her back, which experts say is the safest sleep position in preventing Sudden Infant Death Syndrome (SIDS).
• Shushing sounds -- These sounds imitate the continual whooshing sound made by the blood flowing through arteries near the womb. Karp recommends parents run avacuum cleaner or hair dryer a safe distance from the baby until she falls asleep, then leave a fan or another form of white noise on while she sleeps.
• Swinging -- Every movement mom made while baby was in utero created a swinging motion in the womb. Rocking, swinging movements, car rides and using an infant swing can all help soothe a baby.
• Sucking -- Sucking has its effects deep within the nervous system. It triggers the calming reflex and releases natural chemicals within the brain. This can be accomplished by allowing the baby to suck on the breast, a bottle, a pacifier or even a finger.

"The 5 S's are like the ingredients for making a cake. It doesn't help you to just have the ingredients. You need the whole recipe in order to do it right," Karp explains. "Not all babies are going to need all five of the techniques. Some will be happy with just one, others will need two or three done in an order they prefer. Some will need all five. The key is to see what works for your individual baby."

Karp has found that teaching these techniques works best when parents learn by watching and practicing. So he created a DVD that demonstrates the 5 S's techniques and has developed a Happiest Baby educator program, which certifies parent and infant educators to teach his Happiest Baby class. Karp believes that classes like his will eventually be considered standard education for parenthood, similar to how Lamaze classes became standard preparation for childbirth.

Locally, childbirth educator Kathy Wilson teaches Karp's class at Gracewinds Perinatal Services in Seattle. She says, "Most of the parents who come to us take the class before their baby is born, but if we have a newborn in class, it's a good thing because then we can practice the 5 S's techniques with the baby."Parents who attend the one-day class take home a copy of Karp's DVD, as well as a CD of "Super-Soothing" Calming Sounds, which includes womb noises, a hair dryer and the sound of rain falling on a roof.

Jennifer McArthur, a Happiest Baby educator who teaches at Evergreen Hospital Medical Center in Kirkland and Great Starts Birth & Family Education in Seattle, as well as having her own private practice, says, "We can really reduce child abuse in this country just by teaching this class, since we know that long-term crying is the main reason we have shaken babies." In fact, a baby's consistent cry is the number one reported reason for shaken baby syndrome. And a New York-based study found that 91 percent of parents with a colicky baby experience severe stress and marital problems. Experts advocate that parents of colicky babies should do everything they can to calm their baby and take care of themselves before reaching the point of anger. For some, Karp's techniques offer tricks to pull out of their bag to bring peace and harmony to the whole family.

Mom's fourth trimester

While the first three months can be difficult for babies, the postpartum period also brings hormonal changes, stress and sleep deprivation for mothers, resulting in their own version of the fourth trimester.

Ann Keppler, a Seattle-based parent educator and co-author of Pregnancy, Childbirth and the Newborn, explains, "For mothers, there's a huge event in giving birth. It's a huge identity crisis. Before a baby is born, a woman might define herself by her job or her interests. But after a baby is born, she develops an instinct of being a lioness or protector of this new little life. It's a life-changing event. And women never go back to exactly the way they were before having a baby."

Mia's mother, Lori Garretson of Beacon Hill, describes these deep emotions well. "I'm much more careful, introspective and humble.

It's like you go back to places you were before having the baby, like the midwife's office or work, and the place just feels different. I feel different. It's like it's not even the same place!"

For mothers, the fourth trimester is all about continually finding your new "normal." Most women don't have a first baby and automatically know what to do. And postpartum mothers who already have children have to find a new balance, adjusting to the changed shape of their family and new sibling dynamics. It takes time, trial and error, and a whole lot of support. Understanding why babies act the way they do during their first weeks of life helps give parents the tools they need to better soothe their baby. And that is truly priceless.

Katie Amodei is a Lynnwood-based freelance reporter, mother and stepmother, who has experienced the fourth trimester twice.

The fourth trimester Resources

Books/CDs/DVDs

• The Happiest Baby on the Block, by Harvey Karp, M.D.
• The Happiest Baby on the Block DVD and The Happiest Baby on the Block "Super-Soothing" Calming Sounds CD.
• The Fourth Trimester: And You Thought Labor Was Hard, by Amy Einhorn
• The Fourth Trimester, by Brenda Eheart
• Sleeping with Your Baby: A Parent's Guide, by James J. McKenna, Ph.D.
• The 7 Stages of Motherhood: Making the Most of Your Life as a Mom, by Ann Pleshette-Murphy
• Happiest Baby on the Block classes
  Gracewinds Perinatal Services, Seattle
  206-781-9637
• From Birth to Baby, Seattle
  Contact instructor: 425-228-1903
• Swedish Medical Center, Seattle
  Contact instructor: 253-460-1122
• Community Birth & Family Center, Seattle
  206-720-0511
• Conscious Fathering Program, Seattle
  206-233-0156, ext. 227
• Great Starts Birth & Family Education, Seattle
  206-789-0883
• Evergreen Healthcare Medical Center, Kirkland
  425-899-3000
• Eastside Doula Care, Kirkland
  425-681-0736
• Heart and Home Postpartum Services, Edmonds
  425-775-3936
• Mother Nature Services, Snohomish
  425-397-9757
• Ewa Health Education, Federal Way
  253-946-0136
• Valerie Gulrajani, private instructor, Puyallup
  253-831-0137
• Winds of Change Childbirth, Poulsbo
  360-874-1689
• Mary Anne Murray, private instructor, Shelton
  253-297-5570
• A Labor of Love, Mount Vernon
  360-941-7627

Tips for Effective Swaddling

Double-swaddling keeps a baby's arms and legs tightly wrapped. To do it, try:

• Swaddling with one receiving blanket, then another on top
• Swaddling once with a receiving blanket then putting the swaddled baby in an infant sleep sack
• Using a swaddling product such as SwaddleMe by Kiddopotamus (www.kiddopotamus.com) or the Miracle Blanket (www.miracleblanket.com)