PTH and Hypocalcemia: In our study, given the higher frequency and susceptibility of the female sex to thyroid pathology, female patients < 40 y were at higher risk of developing postoperative hypocalcemia (OR 1.91, 95% CI 1.281–2.943, p < 0.001), and this higher predisposition may be a consequence of the effects of sex steroids on PTH secretion [30], although this association was reported with conflicting results [9,14,21].