IL6 and hydrops fetalis: Significant associations were found between IL-6 and TP (r = −0.34, p = 0.01), LF (r = −0.36, p < 0.01); between IL-18 and pNN50 (r = −0.53, p < 0.01), HF (r = −0.34, p < 0.05); between hsCRP and RMSSD (r = −0.40, p < 0.01), TP (r = −0.35, p = 0.01), LF (r = −0.31, p < 0.05), HF (r = −0.42, p < 0.01); between NO and RMSSD (r = 0.65, p < 0.001), TP (r = 0.30, p < 0.05), HF(r = 0.32, p < 0.05); between eNOS and RMSSD (r = 0.43, p < 0.01). Whereas, ET-1 is not associated with any HRV indices.