Queen's University Belfast

Academic Institute

Estelle Lowry

E069

For centuries, Low Birth Weight (LBW) (<2500g) has been used as the main marker of vulnerability in a newborn, but this is not granular enough to understand the risks and also causes. LBW is due to either being born preterm (<37 completed weeks of gestation) or growth-restricted (defined as <10th centile of birthweight for gestational age (GA) and sex i.e., small for gestational age (SGA)) or a combination of both. Global estimates of LBW do not discriminate between the babies who had LBW due to prematurity versus those linked to fetal growth restriction. Population-level data are available for national estimates of LBW from surveys and routine facility data, and to a lesser extent for the prevalence of preterm birth from routine data. However, there are no reliable multi-country data on the various combinations or phenotypes of vulnerable newborns (i.e. prematurity, fetal growth restriction and the combination). Therefore, this is a collaborative approach involving governments, academics and also WHO and UNICEF and will help set jointly agreed priorities to improve data quality and use of data in programmes for vulnerable newborns all over the world.

Specifically in Northern Ireland in 2017/18 [1], 6.4% of infants were born with a low birth weight classified as <2500g (6.1% of live and 69.3% of still births). In particular, younger and older mothers appeared to be most at risk for a LBW baby shown by percentages of LBW higher than the NI average (7.4% of births to mothers aged under 20 and 8.1% of births to mothers aged 40 and over). Mothers from more deprived areas were also at higher risk, (7.5% of LBW babies born to mothers from most deprived areas compared to 5.5% in least deprived areas). Furthermore, although infant mortality is falling, figures for 2014 showed that NI had the highest infant mortality rate (under one year of age) (4.8 per 1,000 live births) of the four UK nations and the neonatal mortality rate (deaths in the first four weeks of life) for NI is also higher when compared to other UK countries. Stillbirth rates have been increasing slightly from 3.1 to 4.4 per 1,000 live births from 2015 to 2017 and infants delivered pre-term (before 37 weeks) are also increasing from 7.3% in 2011/12 to 8.05% 2017/2018. Thus, as well as being important to contribute to this collaborative effort to inform and educate on worldwide markers of vulnerability, it is also an important exercise for Northern Ireland to undertake to better understand how to identify those at highest risk of adverse effects in order for appropriate interventions to be implemented.

27/09/2021

TRE