Customized versus population birth weight charts for identification of newborns at risk of long-term adverse cardio-metabolic and respiratory outcomes: a population-based prospective cohort study

Abstract

Background: Customized birth weight charts take into account physiological maternal characteristics that are known to influence fetal growth to differentiate between physiological and pathological abnormal size at birth. It is unknown whether customized birth weight charts better identify newborns at risk of long-term adverse outcomes than population birth weight charts. We aimed to examine whether birth weight classification according to customized charts is superior to population charts at identification of newborns at risk of adverse cardio-metabolic and respiratory health outcomes.

Methods: In a population-based prospective cohort study among 6052 pregnant women and their children, we measured infant catch-up growth, overweight, high blood pressure, hyperlipidemia, liver steatosis, clustering of cardio-metabolic risk factors, and asthma at age 10. Small size and large size for gestational age at birth was defined as birth weight in the lowest or highest decile, respectively, of population or customized charts. Association with birth weight classification was assessed using logistic regression models.

Results: Of the total of 605 newborns classified as small size for gestational age by population charts, 150 (24.8%) were reclassified as appropriate size for gestational age by customized charts, whereas of the total of 605 newborns classified as large size for gestational age by population charts, 129 (21.3%) cases were reclassified as appropriate size for gestational age by customized charts. Compared to newborns born appropriate size for gestational age, newborns born small size for gestational age according to customized charts had increased risks of infant catch-up growth (odds ratio (OR) 5.15 (95% confidence interval (CI) 4.22 to 6.29)), high blood pressure (OR 2.05 (95% CI 1.55 to 2.72)), and clustering of cardio-metabolic risk factors at 10 years (OR 1.66 (95% CI 1.18 to 2.34)). No associations were observed for overweight, hyperlipidemia, liver steatosis, or asthma. Newborns born large-size for gestational age according to customized charts had higher risk of catch-down-growth only (OR 3.84 (95% CI 3.22 to 4.59)). The direction and strength of the observed associations were largely similar when we used classification according to population charts.

Conclusions: Small-size-for-gestational-age newborns seem to be at risk of long-term adverse cardio-metabolic health outcomes, irrespective of the use of customized or population birth weight charts.

Keywords: Birth weight; Cardiovascular health; Charts; Child; Customization; Outcomes; Respiratory health.

Fig. 1

a–h Prevalence of birth weight classifications and their association with infant growth patterns and cardio-metabolic and respiratory outcomes at age 10. Bars are prevalence (%, left y-axis) and OR’s (95% CI, right y-axis). Reference groups for OR’s of customized and population classifications are newborns classified AGA according to the respective classification. Prevalences of adverse outcomes among SGA, AGA and LGA newborns were calculated by dividing the number of cases by the number of newborns in each birth weight category. Clustering of cardio-metabolic risk factors is defined as having three or more of the following components: visceral fat mass >75^th percentile; systolic or diastolic blood pressure >75^th percentile; HDL-cholesterol <25^th percentile or triglycerides >75^th percentile; and insulin level >75^th percentile of our study population. ^a SGA was defined as gestational age adjusted birth weight <10^th percentile of the customized chart. AGA is defined as gestational age adjusted birth weight >10^th and <90^th percentile of the customized chart. LGA was defined as gestational age adjusted birth weight >90^th percentile of the customized chart. ^b SGA was defined as gestational age adjusted birth weight <10^th percentile of the population birth weight chart. AGA is defined as gestational age adjusted birth weight >10^th and <90^th percentile the population chart. LGA was defined as gestational age adjusted birth weight >90^th percentile of the population chart

Fig. 2

a–h Prevalence of customized only and population only birth weight classifications and their association with infant growth patterns and cardio-metabolic and respiratory outcomes at age 10. Bars are prevalence (%, left y-axis) and OR’s (95% CI, right y-axis). Reference groups for OR’s of customized and population classifications are newborns classified AGA according to both customized and population classification. Prevalences of adverse outcomes among SGA, AGA and LGA newborns were calculated by dividing the number of cases by the number of newborns in each birth weight category. Clustering of cardio-metabolic risk factors is defined as having three or more of the following components: visceral fat mass >75^th percentile; systolic or diastolic blood pressure >75^th percentile; HDL-cholesterol <25th percentile or triglycerides >75^th percentile; and insulin level >75^th percentile of our study population. ^a SGA was defined as gestational age adjusted birth weight <10^th percentile of the customized chart, but >10^th percentile according to the population chart. AGA is defined as gestational age adjusted birth weight >10^th and <90^th percentile of both the customized and population chart. LGA was defined as gestational age adjusted birth weight >90^th percentile of the customized chart, but not <90^th percentile according to the population chart. ^b SGA was defined as gestational age adjusted birth weight <10^th percentile of the population birth weight chart, but >10^th percentile according to the customized chart. AGA is defined as gestational age adjusted birth weight >10^th and <90^th percentile of both the population and customized chart. LGA was defined as gestational age adjusted birth weight >90th percentile of the population chart, but not <90^th percentile of the customized chart