MTHFR and fetal growth restriction: Single nucleotide substitutions in MTHFR are known to affect enzyme function thus limiting the bioavailability of folate and have been associated with pregnancy complications such as PE and intrauterine growth restriction (IUGR) (Chedraui et al., 2015; Lachmeijer et al., 2001; Liew & Gupta, 2015).