Linear mixed models showed that women carrying females versus males exhibited greater stimulated production of IL-6 at each timepoint (ps⩽0.03), TNF-α in early pregnancy (p=0.04), and IL-1β in mid- and late pregnancy (ps⩽0.05).
In both diseases, active disease and tumor necrosis factor inhibitor (TNFi) discontinuation in early pregnancy were identified as risk factors for disease flares during pregnancy.
Plasma TNF-α levels increase during early pregnancy in RM women regardless of outcome, but are higher in secondary than primary RM, which may be partly genetically determined.