Baseline heart rate in infants with prenatal alcohol exposure: A systematic review and independent analysis.

BACKGROUND: Infants with fetal alcohol syndrome exhibit a range of developmental anomalies, many related to the heart (e.g., decreased heart rate variability). However, the baseline heart rate in this population remains unclear. We hypothesized that the age at which heart rate was measured or the age during exposure to alcohol affects the baseline heart rate. METHODS: First, we conducted a systemic review to determine the published heart rate of infants with prenatal alcohol exposure (PAE). Exclusion criteria included potentially confounding factors, including the commonly associated phenotypes of small for gestational age and premature birth. Risk of bias was evaluated based on case study limitations, and data were compared with established heart rate norms. Then, we evaluated the precise age at heart rate measurement using existing datasets from the Collaborative Initiative on Fetal Alcohol Spectrum Disorders and the Maternal Lifestyle Study. RESULTS: Based on the weighted means of six studies, the baseline heart rate was 4.6 bpm higher in infants with PAE (n = 253) than in control infants (n = 152). Using the individual patient data, baseline heart rates were similar between age-matched infants with PAE and control infants who were born full-term and showed no signs of growth restriction (ANOVA, p > .05; n = 49-124 infants per age and exposure). CONCLUSIONS: A systematic literature review suggested that heart rate is elevated in infants with PAE, but these findings are limited by the number of studies and how few studies included control infants. The analysis of individual patient data indicates that infants with PAE have normal baseline heart rates. This knowledge may help clinicians detect changes in cardiac function in infants with PAE. (Registered via PROSPERO, #CRD42020191212.).