Endogenous relaxin-2 may counteract end-organ damage and consequently provide a long-term treatment with this hormone will benefit patients with HF via the inhibition of inflammation, fibrosis, apoptosis, and oxidative stress; the induction of angiogenesis; and the improvement of the haemodynamics (at systemic, cardiac, and renal levels), together with the relief of congestion and the stimulation of vasorelaxation (Figure 2) [12,15,33,95]. This evidence concerns the gene RLN2 and hydrops fetalis.