The autonomic nervous system (ANS) regulates the body's physiology, including cardiovascular function. As the ANS develops during the second to third trimester, fetal heart rate variability (HRV) increases while fetal heart rate (HR) decreases. In this way, fetal HR and HRV provide an index of fetal ANS development and future neurobehavioral regulation. Fetal HR and HRV have been associated with child language ability and psychomotor development behavior in toddlerhood. However, their associations with postbirth autonomic brain systems, such as the brainstem, hypothalamus, and dorsal anterior cingulate cortex (dACC), have yet to be investigated even though brain pathways involved in autonomic regulation are well established in older individuals. We assessed whether fetal HR and HRV were associated with the brainstem, hypothalamic, and dACC functional connectivity in newborns. Data were obtained from 60 pregnant individuals (ages 14–42) at 24–27 and 34–37 weeks of gestation using a fetal actocardiograph to generate fetal HR and HRV. During natural sleep, their infants (38 males and 22 females) underwent a fMRI scan between 40 and 46 weeks of postmenstrual age. Our findings relate fetal heart indices to brainstem, hypothalamic, and dACC connectivity and reveal connections with widespread brain regions that may support behavioral and emotional regulation. We demonstrated the basic physiologic association between fetal HR indices and lower- and higher-order brain regions involved in regulatory processes. This work provides the foundation for future behavioral or physiological regulation research in fetuses and infants.

自主神经系统 (ANS) 调节身体的生理机能，包括心血管功能。随着 ANS 在妊娠中期到晚期的发展，胎心率变异性 (HRV) 增加，而胎心率 (HR) 降低。这样，胎儿 HR 和 HRV 就提供了胎儿 ANS 发育和未来神经行为调节的指标。胎儿 HR 和 HRV 与幼儿期的儿童语言能力和精神运动发展行为有关。然而，尽管参与自主调节的大脑通路在老年人中已得到很好的证实，但它们与出生后自主脑系统（如脑干、下丘脑和背侧前扣带皮层（dACC））的关联仍有待研究。我们评估了胎儿 HR 和 HRV 是否与新生儿脑干、下丘脑和 dACC 功能连接相关。数据是从 60 名怀孕个体（14-42 岁）在妊娠 24-27 周和 34-37 周时使用胎儿心电图生成胎儿 HR 和 HRV 获得的。在自然睡眠期间，他们的婴儿（38 名男性和 22 名女性）在月经后 40 至 46 周之间接受了功能磁共振成像扫描。我们的研究结果将胎心指数与脑干、下丘脑和 dACC 连接联系起来，并揭示了与可能支持行为和情绪调节的广泛大脑区域的联系。我们证明了胎儿 HR 指数与参与调节过程的低阶和高阶大脑区域之间的基本生理关联。这项工作为未来胎儿和婴儿的行为或生理调节研究奠定了基础。