Plasminogen Activator Inhibitor 1 4G/5G and −844G/A Variants in Idiopathic Recurrent Pregnancy Loss




Plasminogen activator inhibitor type 1 (PAI-1) regulates fibrinolysis, and the common promoter region variants −675G/A (4G/5G) and −844G/A are associated with increased thrombotic risk. Despite evidence linking altered fibrinolysis with adverse pregnancy events, including idiopathic recurrent pregnancy loss (RPL), the contribution of PAI-1 variants to RPL risk remains controversial. We investigated the association between the PAI-1 −844G/A and 4G/5G (−675G/A) variants with altered risk of RPL.

Method of study

This was a case–control study involving 304 women with confirmed RPL and 371 age- and ethnically matched control women. PAI-1 genotyping was performed by PCR single-specific primer −675 (G/A) and real-time PCR (−844G/A) analysis.


Minor allele frequency (MAF) of 4G/5G (< 0.001), but not −844G/A (= 0.507), was higher in RPL cases. PAI-1 4G/5G single-nucleotide polymorphism (SNP) was significantly associated with RPL under additive, dominant, and recessive genetic models; no association of −844G/A with RPL was seen irrespective of the genetic model tested. Taking common −844G/5G haplotype as reference (OR = 1.00), multivariate analysis confirmed the association of 4G-containing −844A/4G (< 0.001) and −844G/4G (= 0.011) haplotypes with increased RPL risk.


4G/5G, but not −844G/A, PAI-1 variant is associated with an increased risk of RPL.