Echocardiographic findings in newborns with inadequate intrauterine growth during pregnancy

Abstract Background Infants born small for gestational age (SGA) or diagnosed with fetal growth restriction (FGR) are at increased risk of neonatal mortality as well as cardiovascular disease later in life. Previous studies based on smaller cohorts (n<200) of newborns with SGA and FGR (n<200) have demonstrated structural and morphological alterations in the heart compared to infants born appropriate for gestational age (AGA). However, to our knowledge no previous study has systematically investigated the effect of SGA and FGR on echocardiographic parameters in the infant heart. Purpose To investigate whether echocardiographic parameters differ among infants born SGA or with FGR, in comparison to infants born AGA. Methods This study is a population-based cohort study of infants (n>25,000) offering postnatal cardiac examination including transthoracic echocardiography (TTE) between 2016-2018. We compared left ventricular (LV) TTE parameters in infants born SGA (birthweight ≥3rd and <10th percentile, n=2,106) and with FGR (birthweight <3rd percentile, n=972) with infants born AGA (birthweight ≥10th and <90th percentile, n=20,468) using a multiple linear regression analysis. We have investigated LV volumes, systolic function, diastolic function, and LV structure. All analyses were adjusted for sex, gestational age at birth, weight, length, and age at cardiac examination. Results Infants born SGA had higher heart rates compared with infants born AGA. Both infants born SGA and infants with FGR had significantly smaller LV dimensions including septal and posterior wall thicknesses (IVSd and LVPWd), and LV internal diameters (LVIDd and LVIDs). Infants born SGA had smaller end-diastolic and end-systolic volumes compared with infants born AGA (Table 1). Infants born SGA or with FGR had significantly higher mitral valve early peak velocities, compared with infants born AGA, and infants born SGA showed increased mitral valve atrial peak velocities indicating altered diastolic function (Table 1). Conclusion Infants born with inadequate intrauterine growth had smaller LV dimensions compared with infants born AGA, even when adjusting for infant size and age. Infants born SGA and with FGR both exhibited altered diastolic function. Longitudinal studies of children with inadequate intrauterine growth are needed to determine the impact on adult cardiac health.