“…The American Society of Endocrinology, however, defined deficiency as being lev-els of 25 (OH) D <50 nmol/L (20 ng/mL), insufficiency as between 52.5 and 72.5 nmol/L (21-29 ng/mL) and optimal or adequate levels as >75 nmol/L (>30 ng/mL) (Holick et al, 2011). Regardless of the proposed cut-off points, it has been observed that vitamin D levels <50 nmol/L during pregnancy are associated with an increased risk of preeclampsia (Wei et al, 2013), gestational diabetes (Wei et al, 2013), being small for gestational age (Santamaria et al, 2018;Wei et al, 2013) and preterm infants (Qin, Lu, Yang, Xu, & Luo, 2016;Wei et al, 2013), while levels of 25 (OH) D <30 nmol/L are associated with low birthweight (Santamaria et al, 2018).…”