KISS1R and spontaneous abortion: The expression levels of the KISS protein and its receptor were not affected by the number of births (Protein: rgamma = 0.031; p = 0.569; n = 214; Figure 6A. Receptor: rgamma = −0.077; p = 0.153; n = 214; Figure 6B) but the level of GPR54 expression slightly (but significantly) decreased with the numbers of the miscarriages (Protein: rgamma = −0.185; p = 0.028; n = 214; Figure 6C. Receptor: rgamma = −0.212; p = 0.010; n = 214; Figure 6D).