IL6 and hydrops fetalis: Gender [i.e. RMSSD (Kunz-Ebrecht et al., 2003; Steptoe and Marmot, 2005)] Cognition [i.e. SDNN (Beer Noa et al., 2017), RSA (Capuana et al., 2012), and HF (Lin et al., 2014)]  Heart rate [i.e. SDNN (Betz Linda et al., 2017)]  Level of physical activity [i.e. RMSSD (Steptoe et al., 2002)]  Respiration (i.e. HF; Crowley Olga et al., 2016)  Smoking and Alcohol Consumption [i.e. RMSSD (Steptoe et al., 2002)]  Stress [i.e. IL-6 response; RMSSD (Hamer and Steptoe, 2007)]  Task type [i.e. verbal vs. spatial; LF (Christensen Stephanie and Wright Heather, 2014)]