The following blog was written by Anne CC Lee, Naoko Kozuki, Joy E Lawn, Joanne Katz for the SGA-Preterm Birth Working Group of the Child Health Epidemiology Reference Group. Photo by Genna Naccache/Save the Children.
Every year, 20 million babies are born with a low birth weight of less than 2500g or 5.5 pounds, making them more vulnerable to illness and death. Babies may be born with a low birth weight because they are born too soon (preterm, defined as <37 weeks completed weeks of gestation) and/or too small (with intrauterine growth restriction – IUGR, or failing to grow optimally in the womb). Preterm birth and IUGR have some different causes and different risks of adverse outcomes, although some babies are both born too soon and too small. Preterm birth has been recently highlighted in the Born Too Soon action report and estimates have been published in the Lancet. Today, preterm birth is the leading cause of newborn deaths; it contributes to other causes of death such as infections, and is also a major cause of long-term impairment. Babies with intrauterine growth restriction also have a higher risk of death and stillbirth, and contribute importantly to long-term stunting and chronic adulthood disease.
In a recent analysis conducted by the Child Health Epidemiology Reference Group (CHERG) we found that growth restricted infants in low- and middle-income countries (LMIC) are 1.8 times more likely to die in the first month of life, compared to non-growth restricted infants. The analysis, which was a collaborative effort that included investigators from over 20 institutions worldwide, found that babies who are both growth restricted and preterm are nearly 20 times more likely to die in their first month of life compared to babies who are neither preterm nor growth restricted.
In the inaugural issue of Lancet Global Health last month, CHERG is releasing the first-ever national estimates of small-for-gestational-age (SGA) and its co-occurrence with preterm birth in low- and middle-income countries for the year 2010. Being SGA is commonly used to indicate intrauterine growth restriction, and is defined as having a birthweight under the 10th percentile for a given gestational age compared to a reference population . In this analysis , 3 million live births in the United States in 1991 were used for comparison.
An estimated 32 million infants were born SGA in low- and middle-income countries in 2010, making up 27% of live births. Of those SGA babies, 11 million were born low birth weight and at full term. Slightly more than half of all low birth weight babies in low-middle income countries are SGA at full term and the other half are preterm.
Two-thirds of SGA babies are born in Asia, with almost half (17 million) in South Asia. The highest numbers of SGA infants were born in India, Pakistan, Nigeria, and Bangladesh. The proportion of babies born SGA at full term ranged from 5% in Eastern Asia to as high as 41% in South Asia.
BORN BOTH TOO SMALL AND TOO SOON
A total of 3 million babies were born both preterm and SGA in 2010. The prevalence of being born both preterm and SGA ranged from 1.2% in Northern Africa to 3.0% in South-eastern Asia.
WHAT CAN BE DONE?
Delaying age at first pregnancy, reducing stunting in girls, improved nutrition in pregnancy and increasing birth spacing may help prevent SGA. Existing interventions which improve the care and survival of preterm and SGA infants have major potential for immediate impact –for example, early feeding support (initiation of breastfeeding, alternative oral feeding methods), Kangaroo Mother Care, early detection and treatment of neonatal infections, and neonatal resuscitation. Yet, these proven, cost-effective interventions often do not reach these babies in greatest need.
To reduce the numbers and improve the survival of babies born too small and too soon, we need to better understand the major causes of both SGA and preterm births and the associated stillbirths, more effectively and equitably distribute existing interventions, and develop and test new solutions. Improving delivery of interventions to women and children early in the lifecycle even before pregnancy, may have a large impact on maternal and neonatal health, as well as on subsequent child and adult health. We know what works and have some tools to act now — to improve the survival of these most vulnerable babies, born either too small or too soon, and also need to be constantly innovating for new and improved tools to protect these vulnerable babies.
> Click here to read the full paper