We report the results of small-angle neutron scattering measurements performed on supercritical heavy water at wave-number transfers between 0.07 and 0.36 Angstrom (-1). The data were collected along five different isochores at temperatures about 1.15, 2.20, and 5.50 degreesC higher than the measured critical temperature. The density, rho, was in the range (rho (c) - 0.062) < rho < (rho (c) + 0.082) g cm(-3), where rho (c) is the critical density. The shape of the scattering spectra is represented by the expression previously used for those measured along the critical isochore [Bonetti , J. Chem. Phys. 112, 268 (2000)]. The temperature and density dependencies of the isothermal compressibility and the correlation length can be reasonably described using a parametric representation of the thermodynamic space and corrections to scaling that include odd terms to account for the asymmetry of the system.