Intrauterine growth restriction is not associated with decreased exercise capacity in adolescents with congenital heart disease

Objective: Multiple studies demonstrate the association of intrauterine growth restriction (IUGR) with impaired aerobic fitness in adolescents and adults. To our knowledge, there are no studies including individuals with the history of both IUGR and congenital heart disease (CHD). Thus, we sought to evaluate the impact of IUGR on exercise capacity in adolescents with CHD. Study Design: We conducted a retrospective chart review of patients <18 years of age who underwent cardiopulmonary exercise testing (CPET) between August 1, 2003 and July 1, 2016. Individuals with birth weight <10th percentile for gestational age were defined as IUGR. Patients with IUGR were matched with non-IUGR patients by cardiac diagnosis and age at CPET. We excluded patients >18 years of age at time of CPET, those without a documented birth weight, gestational age, or Race. Results: A total of 282 patients were included with CHD present in 86 IUGR cases and 86 controls. There was no difference in percent predicted exercise duration (IUGR: 65.2% ± 31.2, non-IUGR: 67.4% ± 27.2; P =.67). Resting heart rate, chronotropic index, percent-predicted peak oxygen consumption, and pulmonary function were similar between groups. Regression analyses confirmed that IUGR was not independently associated with difference in percent-predicted exercise duration. Conclusions: Intrauterine growth restriction is not associated with the differences in the measurements of exercise capacity in adolescents with CHD. These findings contrast earlier studies, showing decreased fitness in individuals with low birth weight but without CHD. To our knowledge, this is the first study to examine the impact of IUGR on exercise capacity in patients with CHD.