What do we mean by newborns and stillbirths?
In this step we’ll outline and describe some of the terminology used throughout this week as there are distinct classifications that it’s important to get right.
Defining newborns and stillbirths
A baby in its first 28 days of life is referred to as a newborn. When a baby dies during the first 27 completed days after birth, it is referred to as a neonatal death.
A fetal death or stillbirth is defined as a baby born with no signs of life at or after 28 weeks’ gestation. The definition is taken from the International Classification of Diseases (ICD-10)1 which also provides thresholds to classify a stillbirth as either a late fetal death, early fetal death, or a miscarriage.
Figure 1 demonstrates the timeline for pregnancies, including definitions of the type of death by the stage at which they occur.
Problems with classification
If a baby is born alive and they show any sign of life before they die, they should be classed as a neonatal death, given a death certificate and included in national data systems. However, there is variation in the application of stillbirth definitions, especially in high income countries. Sometimes, and especially in settings without basic newborn care where the baby is not assessed properly to see if they are breathing or to check for a heartbeat, then a live birth may be misclassified as a stillbirth.
Preterm birth, small gestational age and low birthweight
The highest risks of death in utero, in the neonatal period, and throughout infancy and early childhood, are for small babies. Being born small is either due to being born preterm (‘Born Too Soon’), being born small for gestational age (SGA; ‘Born Too Small’) or a combination of the two.
Preterm birth is defined as before 37 completed weeks (see Figure 1). This is simplistic, and there are steep increases in risk of death at lower gestational ages and some up to 39 weeks so this cut-off may be debated.
Small for gestational age (SGA), defined as below the 10th centile for sex-specific, gestation-specific standards, depends on the standard used. Estimates were previously based on a US growth standard, but an international standard has now been provided by the InterGrowth study.3
Traditionally, low birthweight (<2500g) (LBW) has been used as a marker of small babies at highest risk of mortality and morbidity during the neonatal period and infancy, as well as of long-term developmental and physical health consequences, including effects on growth, insulin resistance and cardiovascular health. With around 20 million (15%) of all newborns worldwide born with a low birthweight each year, this group represents a substantial burden. The <2500g LBW cut-off is also simplistic due to risk being aligned to birth size and gestational age especially. More detailed studies are critical for understanding and reducing the burden. Unfortunately, in the highest burden settings, less than half of babies are weighed at birth, and fewer have accurate gestational age dating to delineate preterm and SGA. Whilst considerable progress has recently been made for estimating the burden of preterm and SGA, much remains to be done to improve the input data.
Stillbirths in your country
The definition used for stillbirths in some countries varies from the WHO standard of >1000 grams or >28 weeks gestation. What definition for stillbirth is used in your country? Are the data publicly available or hard to find? How would you describe attention for stillbirths in your country?
© London School of Hygiene & Tropical Medicine