Devices, systems, and methods for monitoring health parameters of an individual, including circumferential changes to a portion of the individual's body, are provided herein. A monitoring device includes: a stretchable component configured to fit securely around a body portion, and a sensor module coupled thereto. The sensor module is configured to obtain and transmit a circumference measurement of the body portion. The sensor module may be further configured to obtain and transmit measurements of one or more additional parameters. A related monitoring system includes the described monitoring device and a mobile computing device. The mobile computing device is configured, at least in part, to: process the circumference measurements to identify and analyze any change in circumference of the body portion, and generate a relevant alert output. Methods performed by the various devices and systems are also provided.