Further, we preliminarily revealed the process of PTL: infection changes the composition of a specific miRNA in the trophoblast sEVs (notably miR-25-3p), which twisted the signal transmitted to maternal HMSMs, thus affected the expression of Cav3.2 and SERCA2a, stimulated Ca2+ oscillation, triggered HMSM contraction, and resulted in PTL. Here, CACNA1H is linked to infection.