There was no effect of PO iron on the average change in Hb value between admission and delivery after adjusting for pre-eclampsia (difference in means: 0.158, CI: -0.580, 0.895; p=0.668) or PPROM (difference in means: 0.113, CI: -0.605, 0.832; p=0.752; see Figure 4). This evidence concerns the gene GSTM1 and preterm premature rupture of the membranes.