Systemically, increased adipose tissue accumulation, as seen in obesity, can lead to increased production of interleukin 6 (IL-6), interleukin IL-1β (IL-1β) and tumor necrosis factor (TNF-α) [89], pro-inflammatory cytokines able to disrupt the immune response at the maternal–fetal interface. Here, IL6 is linked to obesity due to melanocortin 4 receptor deficiency.