A method to identify women who are at risk for preterm delivery due to premature rupture of membranes (PPROM) is provided. The method entails detecting the presence of SERPINH1 gene variants that express low levels of the gene product, heat shock protein Hsp47. The occurrence of a T (rather than C) at a single nucleotide polymorphism (SNP) site at position −656 of the SERPINH1 gene promoter, together with the absence of a 12 base pair deletion at positions −694 to −683 of the promoter, result in an increased risk of PPROM. The method enables medical professionals to identify those at risk, and to provide suitable therapeutic intervention.