For example, elevated levels of interleukin (IL) IL-1β, IL-6, tumor necrosis factor alpha (TNFα) and C-reactive protein (CRP) (Scrandis et al., 2008; Christian et al., 2009; Cassidy-Bushrow et al., 2012; Azar and Mercer, 2013; Haeri et al., 2013), and of corticotrophin releasing hormone (CRH) and cortisol (Rich-Edwards et al., 2008; O’Keane et al., 2011; O’Connor et al., 2013b), have all been described in association with antenatal symptoms of depression. Here, IL6 is linked to major depressive disorder.