Therefore, the aim of the present study is to investigate the association between variants in candidate genes—namely, BMAL1 rs7950226 (G>A), CLOCK rs1801260 (A>G), CLOCK rs4864548 (G>A), and CLOCK rs3736544 (G>A)—and overweight/obesity in 291 pregnant women. This evidence concerns the gene CLOCK and obesity due to melanocortin 4 receptor deficiency.