Fluctuations in steroid sex hormones are associated with altered cardiac autonomic and affective functioning across the female lifespan. The neuroendocrine pathways which modulate sex hormone changes during the menstrual cycle have reciprocal interactions with the autonomic nervous system, an integral system for self-regulation and stress response. Cardiac autonomic activity is often imbalanced among individuals with mental and physical health conditions. However, it is unclear whether variations in female-typical sex hormones across the menstrual cycle significantly alter cardiac autonomic and affective stress reactivity, which may underlie menstrual-related mood and psychosomatic symptoms. The present systematic review aims to address this gap by characterizing patterns of cardiac autonomic activity at baseline, and cardiac autonomic and affective reactivity to laboratory stress tasks across the menstrual cycle in reproductive-aged women. The review was preregistered (https://doi.org/10.17605/OSF.IO/B2Y5Q) and conducted in line with PRISMA guidelines. Twenty studies and 28 records were identified and discussed. The study found modest support for increased cardiac sympathetic activation at baseline and in response to stress, and greater affective reactivity within the luteal phase of the menstrual cycle. These results expand upon prior research demonstrating cardiac autonomic imbalance and affective vulnerability within the luteal phase to show that these patterns also influence stress reactivity. Additionally, the review aims to identify notable methodological limitations and gaps within this body of literature and suggests areas of future research to clarify the role of cardiac autonomic and affective processes in steroid sex hormone-related symptomatology.