  In this paper, we study gravitational waves generated by binary systems
within an extension of General Relativity which is described by the addition of
quadratic in curvature tensor terms to the Einstein-Hilbert action. Treating
quadratic gravity as an effective theory valid in the low energy/curvature
regime, we argue that reliable calculations can be performed in the early
inspiral phase, and furthermore, no flux of additional massive waves can be
detected. We then compute the massive dipole (-1PN) leading corrections to the
post-Newtonian (PN) expansion of the standard waveform. By confronting these
theoretical calculations with available experimental data, we constrain both
unknown parameters of quadratic gravity to be $0 \leq \gamma \, \lesssim
5.7\cdot 10^{76}$, and $-\frac{\gamma}{4} \leq \beta \, \lesssim - 4.2\cdot
10^{75}$.
