Babies are at greater risk than previously thought of becoming dangerously dehydrated because of inadequate nourishment from breastfeeding.

Health professionals and mothers need to do a better job of recognizing what is a preventable problem, said Dr. Michael Moritz, a nephrologist at Children's Hospital.

"There are some significant complications that can be associated with breastfeeding, and the complications are more common than people generally perceive," he said.

The problems are not a reason to avoid breastfeeding, but mothers should be taught what to look for and when to have the child examined, Dr. Moritz said.

He recommended that babies be evaluated within two days of being discharged from the hospital. If a baby has lost 7 percent or more of body weight, then the doctor should assess whether breastfeeding is going properly.

Dr. Moritz led a research team that found that one out of 50 infants in the first month of life admitted to Children's had hypernatremic dehydration, which is dehydration with high blood sodium levels.

The researchers estimated that the complication occurs in one of every 200 babies in the general community. The findings were published in the September issue of Pediatrics.

"For a lot of reasons, the baby is at risk for dehydration during that first week of life," Dr. Moritz said. "What we're finding is that pediatricians and parents really weren't able to pick up on these complications."

Sometimes mothers, particularly those who have just had their first baby, are not physiologically able to make enough milk. It can take some time for ducts to develop fully and milk to come in, he said.

Also, inexperienced moms might find it difficult or uncomfortable to latch their babies onto the breast properly and to let them nurse for sufficient time.

"The bottom line is, if the milk is not coming in, the infant would have to be supplemented with formula until the problem can be corrected," Dr. Moritz said.

He added, "If there's a reluctance to supplement with either expressed breast milk or infant formula until proper lactation can be established, we're placing these children at risk."

Dr. Moritz cautioned that giving a bottle while waiting for breast milk to come in will not work. The breasts must be regularly stimulated to produce milk.

And dehydration "wouldn't be a reason to discontinue breastfeeding," he said. "Many of these children who had these complications, the mothers were able to resume breast feeding."

Dr. Nancy Brent, medical director of the Maternal Infant Lactation Center at Mercy Hospital, said much of the time supplementing is recommended when it's unnecessary.

Hypernatremic dehydration is "a preventable condition and one that really should never happen if we can manage the breastfeeding situation correctly," said Dr. Brent, who was not a member of the research team.

Parents and doctors can and should be taught what to look for to ensure babies are getting sufficient nourishment though nursing.

If the baby is properly latched to the breast, mom should see the baby's jaw move and hear the sounds of suckling and swallowing, Dr. Brent said. The baby should be satisfied after the feeding.

Newborns should be eating eight to 12 times per day by the end of the first week of life.

"The mother sometimes feels like she's doing absolutely nothing at all except nursing the baby," Dr. Brent said. "I usually tell them if that's the way they feel, everything is going right."

Moms should wake their babies every three hours during the day if they are not waking up to eat on their own.

"[A mother] shouldn't let the baby sleep four or five hours at a stretch, as tempting as it may seem," Dr. Brent said.

Also, week-old babies should urinate six to eight times daily and have three to five bowel movements daily.

"If the mother is at all concerned, she should take the baby in for a weight check," which is the best way to tell if there's a feeding problem, Brent said.

Mothers can express or pump breast milk if a bottle becomes necessary, but there are ways to supplement that don't require a bottle.

"You can use a cup like a small medicine cup that's very flexible and the baby kind of laps up the milk," Dr. Brent said. "You can use an eye dropper or a teaspoon."

Bottles are available with special long tubes that are placed alongside the breast let the baby simultaneously bottle and breastfeed, she added.

"That provides stimulation to the mom for the milk supply, but assures that the baby is not going to go without milk," Brent explained.

The vast majority of women are able to breastfeed successfully, but they and their doctors need more education about how to do it.

In societies where breastfeeding is the tradition, new mothers can turn to their mothers, sisters and friends for advice, and complications are uncommon, Dr. Brent said.

The federal government, in its Healthy People 2010 guidelines, would like to see 75 percent of all mothers breastfeeding after delivery, and at least 50 percent still breastfeeding when their children are 6 months old. In 1998, when the guidelines were developed, about 64 percent of mothers breastfed.

According to 2003 data from the state Department of Health, 60 percent of mothers in Allegheny County said they intended to breastfeed, which is just shy of the statewide figure of 61 percent.

"There have been any number of studies . . . that have shown if we support women both during pregnancy and postpartum, we can increase breastfeeding initiation and duration," Dr. Brent said. "We just have to have the resources and committment to do that."