42), Menon et al. (Ref. 22) and Plunkett and Muglia (Ref. 7) suggested an association between PTB and TNF receptors 1 (TNFR1) and 2 (TNFR2) genes. Kalish et al. (Ref. 44) found that TNFRSF6 (tumour necrosis factor receptor superfamily member 6 or Fas gene) was associated with an increased risk of PPROM. Toll-like receptors are proinflammatory agonists, gene variants of which were associated with an increased risk of PPROM as reported by Ramos et al. (Ref. 40) and Romero et al. (Ref. 36) (Table S1). Here, TNFRSF1B is linked to preterm premature rupture of the membranes.