Breastmilk and better school-age outcomes for preterm children

Feeding with maternal breastmilk in the first weeks and months of a preterm infant’s life may lead to better neurodevelopmental outcomes at school age. GPs have an important role to play in promoting the benefits of breastmilk.

EVERY year in Australia, more than 24 000 babies are born preterm (before 37 weeks’ gestation). Children born preterm have an increased risk of poor cognitive, motor and academic performance and have more behavioural disorders than those born at term. The risks of impairment are greatest in those born at the earliest gestational ages and can have a profound impact on the quality of life of the individual and their family.

Recent research by our group, published in JAMA Network Open, suggests that improving the intake of maternal breastmilk, particularly in the first few weeks and months of a preterm infant’s life, can help mitigate the risk of long term neurodevelopmental impairment.

Our study involved 586 infants born at less than 33 weeks’ gestation across five Australian perinatal hospitals. Infants were recruited in the newborn period and neurodevelopment was assessed across early childhood. Detailed feeding information was collected, which enabled our team to determine the volume of maternal breastmilk infants received each day during the neonatal hospitalisation, as well as the total duration in months of maternal breastmilk intake up to 18 months of age. At 7 years of age (corrected for prematurity) we assessed IQ, academic achievement (spelling, reading and maths abilities), symptoms of attention deficit/hyperactivity disorder (ADHD), executive functioning, and behavioural difficulties.

What did we find?

Overall, a higher daily intake of maternal breastmilk during the neonatal hospitalisation was associated with higher performance IQ and higher reading and maths scores at 7 years of age. In addition, parents reported fewer ADHD symptoms among children who consumed more maternal breastmilk during the hospitalisation. We also found that a longer duration of maternal breastmilk intake beyond the neonatal hospitalisation was associated with higher reading, spelling and maths scores.

These beneficial associations were generally stronger (2- to 3-fold higher in magnitude) for infants born at the lowest gestational ages, particularly for those born below 30 weeks’ gestation. Importantly, the size of the differences found are clinically meaningful in terms of predicting longer-term outcomes such as attaining tertiary education. The associations remain after controlling for confounding factors related to family background, such as maternal education and other socioeconomic factors, and for clinical factors during the pregnancy and birth.

What do these findings mean?

The short term benefits of breastmilk for preterm infants are well known and include a reduced risk of infections (gastrointestinal, respiratory and ear), severe gut complications, and vision problems associated with prematurity. Our research suggests that there may be benefits years later for neurodevelopmental outcomes.

Yet prematurity poses unique challenges for establishing breastfeeding. Mothers of preterm infants often have difficulties producing enough breastmilk, due to illness and stress associated with having a preterm birth and being separated from their infant (or infants) when they are admitted to a neonatal unit.

Feeding a preterm infant often begins by providing small volumes of milk via a tube followed by a gradual progression to suck feeding, as the infant learns to coordinate sucking, swallowing and breathing. This may take several weeks, and the earlier a baby is born, the longer it will take. This means mothers need to regularly express breastmilk in order to build and maintain an adequate supply for their infant in the longer term. When infants are only tolerating small volumes of milk, fortifiers are often added to breastmilk to provide extra calories needed to support growth.

When maternal breastmilk is in short supply or not available, preterm infants may be given pasteurised donor human milk (“donor milk”) or infant formula during the neonatal hospitalisation. Preterm infant formulas are derived from cow’s milk with added nutrients to meet the nutritional needs of preterm infants, but they do not contain the unique constituents of maternal breastmilk, particularly those that provide immunological and gut protection. Donor milk is breastmilk provided by another breastfeeding mother that is pasteurised to kill bacteria and viruses. Donor milk provides some protection against severe gut complications, yet the pasteurisation process may modify some of the beneficial components of breastmilk. While not available at the time of our study, donor milk is now routinely provided to hospitalised infants born under 32 weeks’ gestation, usually as a supplement while maternal breastmilk supply is being established.

The findings of our research emphasize the importance of providing early support for initiating lactation in mothers who give birth preterm. This includes teaching mothers how to express breastmilk early after a preterm birth, and frequently thereafter to help build and sustain their milk supply. Early skin to skin contact has also been shown to help with the establishment of breastfeeding.

Support needs to continue during and after the hospitalisation to help mothers sustain lactation and make a successful transition from expressing breastmilk to breastfeeding when their infant is developmentally ready. Many neonatal nurseries will have a lactation consultant on staff to support mothers while they or their infant are still in hospital. This is a critical resource for breastfeeding support. Previous research shows access to lactation consultants improves rates of breastmilk feeding among preterm infants and can help to reduce anxiety around building an adequate supply of breastmilk.

One of the most important strategies to promote high breastfeeding rates is parental breastfeeding education. This can be accessed via antenatal breastfeeding education classes at maternity hospitals, from organisations such as the Australian Breastfeeding Association and from perinatal health care providers.

GPs have an important role in discussing the short and long term benefits of breastmilk with pregnant women. This includes the importance of early initiation of breast-milk expression following a preterm birth, particularly as most preterm births occur spontaneously. GPs can also assist women to access existing breastfeeding education, resources and community-based services, both during pregnancy and after birth. By supporting increased breastmilk feeding in preterm infants, this will not only improve short term health but continue to benefit children when they reach school age.

Associate Professor Alice Rumbold is a Principal Research Fellow and co-director of the Pregnancy and Perinatal Care Group at the South Australian Health and Medical Research Institute.

Dr Jacqueline Gould is a Postdoctoral Research Fellow in the Child Nutrition Research Centre at the South Australian Health and Medical Research Institute. 

Professor Maria Makrides is a National Health and Medical Research Council Principal Research Fellow and Theme Leader for Women and Kids and Deputy Director of the South Australian Health and Medical Research Institute.

The statements or opinions expressed in this article reflect the views of the authors and do not necessarily represent the official policy of the AMA, the MJA or InSight+ unless so stated.

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