No, an at-home fetal doppler should not be used as a replacement for ultrasound. While fetal dopplers can be a helpful tool for monitoring fetal heart rate at home, they are not as accurate as ultrasound and cannot provide the same level of diagnostic information as medical ultrasound. Ultrasound uses sound waves to create images of the fetus and can detect potential abnormalities, while fetal dopplers only detect the fetal heart rate. It is important to consult with a healthcare provider and receive regular medical care during pregnancy, including ultrasounds, to ensure the health and safety of both the mother and the baby.