After adjustments, IL-1α was associated with SDNNI and RMSSD; IL-4 was associated with SDNNi, RMSSD, and LF; IL-12p70 was associated with SDNN, SDNNi, RMSSD, VLF, and LF; and TNF-α was associated with SDNNi, RMSSD, VLF, LF, and HF. Here, TNF is linked to hydrops fetalis.