This 100 ng/ml IL-6 concentration is much higher than observed in steady state maternal serum (Graham et al., 2018) yet it would be expected that IL-6 concentration increases in maternal serum during an acute response to infection (Hsiao and Patterson, 2011, Matelski et al., 2021, Ozaki et al., 2020, Wu et al., 2017). Here, IL6 is linked to infection.