Study aims to increase breastfeeding success in mothers of premature babies

Stanford Report, April 14, 2004

Study aims to increase breastfeeding success in mothers of premature babies
Grant gives funds to analyze volume and composition

By KRISTA CONGER

Most of us wouldn't associate the gentle whir of a breast pump with the neonatal intensive care unit. But premature babies who receive breast milk leave the hospital an average of two weeks sooner than those who are formula-fed, and they are less likely to suffer from life-threatening infections or bowel disease. Providing breast milk is also a powerful way for mothers to participate in their baby's care.

"Many mothers who deliver prematurely feel that they have abdicated the care of their baby to the high-tech nursery," said Jane Morton, MD, director of the Breastfeeding Medicine Program at Lucile Packard Children’s Hospital. "Providing breast milk is one vital connection that can be more useful than many of the medical procedures we can offer the baby."

The difficulties of breastfeeding increase exponentially, however, when a premature baby is too small, weak or uncoordinated to nurse effectively. These mothers must rely on breast pumps to extract the milk, which is then given to their infants through a feeding tube. Morton recently received a $160,000 grant from Medela Corp., a breast pump manufacturer, to study which breast pump models and equipment are most effective in helping a new mother establish and maintain a healthy milk supply for her infant.

"Some mothers are pump-dependent for months," said Morton. "The tinier the baby, the longer the mother is going to need to use the pump. However, because milk production plateaus after the first two weeks, it's important to ramp up quickly even though the baby is still very small."

A strong "letdown response" is a critical component of successful pumping or breastfeeding. Letdown is a physiological response to suckling that increases milk flow to the nipple and allows complete emptying of the breast, which stimulates the body to produce more milk. If the breast is not regularly and completely drained the body cuts back and eventually eliminate milk production.

Establishing a high volume of milk early is critical to allow the baby to eventually switch from feeding tube or bottle to the breast, said Morton. "Without that volume the milk is too difficult for the baby to access, setting the mothers up for early termination of breast milk feeding." Frustrated and tired moms, who must offer their babies a bottle after first trying to breastfeed, may not have the stamina to follow up with a pumping session to empty their breasts and stimulate more milk production.

Mothers of premature babies weighing less than 1,500 grams (3.3 pounds) who choose to participate in Morton's study will be randomized to one of two different breast pumps: one with a special "pre-letdown" setting and another, a standard model with only the extraction pumping pattern. Morton will compare the volume of milk produced by mothers using each pump.

Another phase of the study will compare letdown intensity and milk production volumes when using breast shields -- the portion of the breast pump that cups the breast -- varying in size, shape and texture. "The manufacturers are finally addressing the obvious," said Morton. "Not all women are shaped the same."

Morton will also collect breast milk samples from women once a day during the first two weeks, and then once a week for the remainder of the six-week study. She'll look at the amounts of about 20 different common components of breast milk, tracking how they change over time.

"This is the really exciting part of the study for me," said Morton. "We're interested in how the milk may vary between moms whose babies were born at different gestational ages. Are the levels of some components, like protein, higher in some women, and do they vary throughout the course of the day? We know that breast milk from women who deliver prematurely tends to have higher protein and salt content, and it will be interesting to see how these levels may change as the baby ages."

Most breast milk fed to premature babies in this country is fortified with calcium, protein and other components based on biochemical markers in the baby's blood. Morton's research may help physicians decide if and when fortification is appropriate.

"We need to learn more about handling a premature baby's nutritional needs," said Morton. "As mothers enroll in this study and become dedicated to pumping at a high level, the benefits for mother and child may become more evident to the staff who cares for them."

Packard program addresses science of breast-feeding (1/29/03)

Leading breastfeeding researcher to give series of talks (3/12/03)