As a maternity nurse, Carla Stetser, 34, knows her way around babies.

But one night her own baby daughter was crying — "screaming at the top of her lungs" — and nothing  Stetser did  could calm or console her. In spite of all her expertise, Stetser was coming up empty.

But then she remembered advice from an informational video shown to mothers who have had babies at AtlantiCare Regional Medical Center, where Stetser works and where her daughter and 5-year-old son were born.

"I gave [the baby] to my husband and walked away," said Stetser, of Galloway, Atlantic County. "It's nice to get a break even for five minutes. It gives you a chance to collect your thoughts."

That advice is at the heart of an educational program aimed at supporting parents — and even saving babies' lives.

The Period of PURPLE Crying helps parents and other caregivers  understand  the frustrating, prolonged crying episodes in infants that can lead to shaking or abuse. Created more than 15 years ago by the Utah-based National Center on Shaken Baby Syndrome, the program has spread to thousands of hospitals in the United States and around the world.

Each letter in the acronym PURPLE represents a different characteristic of the crying:

P: The crying usually peaks at age 2 months, then declines;
U: It is often unexpected;
R: The child resists soothing;
P: The child makes a face that may look like she is in pain;
L: The crying is long-lasting;
E: It tends to be most prolonged in the evening and late afternoon.

"All babies go through it, and for some it is five to six hours" in a day, said Ryan Steinbeigle, executive director of the national center.

The episodes can cause stress and frustration for already sleep-deprived parents. At worst, the aftermath is tragedy.

Abusive head trauma, which includes shaken baby syndrome, causes a third of physical child abuse deaths in children under 5, according to the U.S. Centers for Disease Control and Prevention. The most common trigger: inconsolable crying.

Babies under 1 year of age are at the greatest risk.  Their heads are heavy and large compared with the rest of their bodies. Their neck muscles are weak. Their developing brains are fragile and vulnerable.

Of the more than 1,300 cases of such head trauma a year in the United States, about one-fourth die, according to the National Center on Shaken Baby Syndrome. Eight in 10 survivors  suffer lifelong disabilities, including learning or speech impairments, paralysis, seizures, or blindness.

The PURPLE program seeks to avoid this damage through information and understanding. One study of the program in British Columbia still underway is showing a nearly 40 percent decrease in incidents, Steinbeigle said. The program materials include a booklet and videos and often a bedside discussion by hospital personnel.

In New Jersey, the program is in 13 hospitals including AtlantiCare in Pomona and, as of last month, at Virtua Voorhees Hospital and Virtua Memorial Hospital in Mount Holly.

Pennsylvania law since 2002 calls for hospitals to provide education about shaken baby syndrome. Thomas Jefferson University Hospital, for example, ensures that the parents of the nearly 2,000 babies born there each year receive information through the statewide Pennsylvania Shaken Baby Syndrome Prevention and Awareness Program, which was based on a  successful New York State initiative founded by Mark Dias, now director of pediatric neurosurgery at Penn State Hershey Medical Center. The parents of about 1.5 million babies have been educated through the Pennsylvania program, said Kelly Cappos, nurse coordinator of the effort. Some outpatient sites also provide education from the PURPLE program, she said.

In the Garden State, "the feedback has been fantastic,"  said Gina Hernandez, vice president of programs for Prevent Child Abuse New Jersey, a statewide nonprofit that is a partner in the PURPLE  program. Nurses, who provide much of the one-on-one education, and patients have given the program strong reviews, she said.

At Virtua, where there are about 8,000 births each year, the bedside discussions and materials are given to all mothers of newborns and are being made available to emergency room visitors.

"We encourage this be shared with anyone who is going to take care of a baby," said Barbara Hansen, Virtua's assistant vice president for Maternal Child Health.

Brooke Jacobs, Virtua's assistant nurse manager of the Mother-Baby Unit,  said it's essential to make sure mothers and all caretakers know that "sometimes, babies cry for no reason."

Maria Sosa, 35, of West New York, N.J.,  received the materials a few months ago. Though her son is now nearly 3, and her daughter is almost 18 months, she still found the information useful, sharing it with the children's father and other family members who may help care for the children.

Just having the validation that a crying baby doesn't mean you are a bad mother has helped her through rough patches.

"It's hard. The pressure is there," Sosa said. "You're a mother. You want to soothe your baby."

Gulzada Syrymbekova, 26, an Atlantic City resident who came to the U.S. as student from Kyrgyzstan in Central Asia, also praised how the program has helped her with her baby girl.

"Being a first-time mom is difficult, so knowing different techniques on how to soothe a crying baby is everything," said Syrymbekova, a former hotel worker who plans to study business.

Daniela Sarabio, 18, and Leafar Camuy, 17, of Pleasantville, Atlantic County, are raising their son, Kenay Camuy, 2, together. While mom and dad attend class at a state program for teen parents, their baby is nearby at the campus child-care center.

Through PURPLE Crying, Sarabio said she has learned it is OK to take a break as long as  another responsible person can take over. For instance, if Kenay is particularly inconsolable, she will hand him to his dad, and she will go take a shower so she can come back refreshed.

The program "helped a lot because this was my first baby," Sarabio said in Spanish through a translator. "Everything that the paper said to expect happened."

Her PURPLE advice for other new parents:  "Tell them to have patience."