Importance Being born small for gestational age (SGA), approximately 10% of all births, is associated with increased risk of cardiovascular mortality in adulthood, but mechanistic pathways are unclear. Cardiac remodeling and dysfunction occur in fetuses SGA and children born SGA, but it is uncertain whether and how these changes persist into adulthood.

Objective To evaluate baseline cardiac function and structure and exercise capacity in young adults born SGA.

Design, Setting, and Participants This cohort study conducted from January 2015 to January 2018 assessed a perinatal cohort born at a tertiary university hospital in Spain between 1975 and 1995. Participants included 158 randomly selected young adults aged 20 to 40 years born SGA (birth weight below the 10th centile) or with intrauterine growth within standard reference ranges (controls). Participants provided their medical history, filled out questionnaires regarding smoking and physical activity habits, and underwent incremental cardiopulmonary exercise stress testing, cardiac magnetic resonance imaging, and a physical examination, with blood pressure, glucose level, and lipid profile data collected.

Exposure Being born SGA.

Main Outcomes and Measures Cardiac structure and function assessed by cardiac magnetic resonance imaging, including biventricular end-diastolic shape analysis. Exercise capacity assessed by incremental exercise stress testing.

Results This cohort study included 81 adults born SGA (median age at study, 34.4 years [IQR, 30.8-36.7 years]; 43 women [53%]) and 77 control participants (median age at study, 33.7 years [interquartile range (IQR), 31.0-37.1 years]; 33 women [43%]). All participants were of White race/ethnicity and underwent imaging, whereas 127 participants (80% of the cohort; 66 control participants and 61 adults born SGA) completed the exercise test. Cardiac shape analysis showed minor changes at rest in right ventricular geometry (DeLong test z, 2.2098; P = .02) with preserved cardiac function in individuals born SGA. However, compared with controls, adults born SGA had lower exercise capacity, with decreased maximal workload (mean [SD], 180 [62] W vs 214 [60] W; P = .006) and oxygen consumption (median, 26.0 mL/min/kg [IQR, 21.5-33.5 mL/min/kg vs 29.5 mL/min/kg [IQR, 24.0-36.0 mL/min/kg]; P = .02). Exercise capacity was significantly correlated with left ventricular mass (ρ = 0.7934; P < .001).

Conclusions and Relevance This cohort of young adults born SGA had markedly reduced exercise capacity. These results support further research to clarify the causes of impaired exercise capacity and the potential association with increased cardiovascular mortality among adults born SGA.

重要性 出生时小于胎龄儿 (SGA)，约占所有新生儿的 10%，与成年期心血管死亡风险增加有关，但机制途径尚不清楚。心脏重塑和功能障碍发生在胎儿 SGA 和出生 SGA 的儿童中，但不确定这些变化是否以及如何持续到成年期。

目的 评估出生 SGA 的年轻人的基线心脏功能和结构以及运动能力。

设计、环境和参与者 本队列研究于 2015 年 1 月至 2018 年 1 月进行，评估了 1975 年至 1995 年间在西班牙一所三级大学医院出生的围产期队列。参与者包括 158 名随机选择的 20 至 40 岁出生 SGA（出生体重低于第 10 个百分位数）或宫内生长在标准参考范围内（对照）。参与者提供了他们的病史，填写了有关吸烟和身体活动习惯的问卷，并接受了增量心肺运动压力测试、心脏磁共振成像和体格检查，并收集了血压、血糖水平和血脂数据。

曝光 出生 SGA。

主要结果和措施 通过心脏磁共振成像评估心脏结构和功能，包括双心室舒张末期形状分析。通过增量运动压力测试评估运动能力。

结果 该队列研究包括 81 名出生为 SGA 的成年人（研究中位年龄，34.4 岁 [IQR，30.8-36.7 岁]；43 名女性 [53%]）和 77 名对照参与者（研究中位年龄，33.7 岁 [四分位距（IQR） )，31.0-37.1 岁]；33 名女性 [43%])。所有参与者都是白人种族并接受了影像学检查，而 127 名参与者（80% 的队列；66 名对照参与者和 61 名出生 SGA 的成年人）完成了运动测试。心脏形状分析显示，在出生 SGA 的个体中，静息时右心室几何形状发生了微小变化（DeLong 检验z，2.2098；P  = .02），但心脏功能保持不变。然而，与对照组相比，出生 SGA 的成年人运动能力较低，最大工作量减少（平均 [SD]，180 [62] W vs 214 [60] W；P = .006）和耗氧量（中位数，26.0 mL/min/kg [IQR，21.5-33.5 mL/min/kg 对比 29.5 mL/min/kg [IQR，24.0-36.0 mL/min/kg]；P  = . 02)。运动能力与左心室质量显着相关（ρ = 0.7934；P  < .001）。

结论和相关性 这组出生为 SGA 的年轻人的运动能力显着降低。这些结果支持进一步研究，以阐明运动能力受损的原因以及与出生 SGA 成人心血管死亡率增加的潜在关联。