Similar findings emerged from the study conducted by Kalkwarf et al. [37], noting serum PTH to be 30% lower in lactating women (n = 97) at baseline, compared to non-lactating women (n = 99) (p < 0.001); it should be noted, however, that neither Grill et al. [41] nor Kalkwarf et al. [37] assessed patients with underlying hypoparathyroidism. Here, PTH is linked to hypoparathyroidism.