Smart healthcare is changing the healthcare industry significantly. Medical image transmission is an indispensable part of smart healthcare. In such a scenario authentication and integrity of medical images is of significant importance. Digital image watermarking in medical images plays a key role for ensuring the authenticity, integrity, and confidentiality of sensitive patient data. This paper introduces CEFQCM, a robust watermarking technique tailored for medical images, employing a two-level Discrete Wavelet Transform (DWT) coupled with a quantization coefficient modulation method. The process begins with the application of DWT on the host image, followed by a secondary DWT on the LH band to produce the LH1 band. The watermark bits are embedded by modifying the quantized coefficients of LH1 band based on their parity in relation to the watermark bit, with adaptive adjustments to maintain imperceptibility while ensuring robustness. The proposed method achieves a mean PSNR of around 42 dB, ensuring the watermark’s imperceptibility and maintaining image quality. Furthermore, the scheme exhibits strong resilience to cropping attacks, surpassing the robustness level of various cutting-edge techniques. CEFQCM provides a reliable and efficient solution for protecting the integrity of medical images, thereby safeguarding sensitive medical information in clinical and diagnostic environments.