Introduction: Epigenetic study among primigravida with major placenta praevia is needed for a better understanding of the disease as well as to reduce both maternal and fetal morbidity and mortality. The aim of the study was to investigate the methylation status of the urokinase plasminogen activator (UPA) and tissue plasminogen activator (TPA) promoter in the placental tissue of primigravida with major placenta praevia compared to non-placenta praevia. We also determine the expression of the transcript level of plasminogen activator tissue (PLAT), serpin peptidase inhibitor (SERPINE), and proline-rich acidic protein (PRAP) gene in the same cohort of primigravida with major placenta praevia compared to non-placenta praevia (controls).

Methods: A cross-sectional comparative study was performed among 24 primigravida in two groups (major placenta praevia vs non-placenta praevia) from January 2013 to January 2014 in a teaching university hospital in Kuala Lumpur. Following the research ethics approval, the recruitment was performed in the maternity unit prior to the elective caesarean delivery. Clinical assessment was carried out before sampling of the placental tissue during caesarean section. Taqman polymerase-chain reaction and methylation study were done on the gene of interest. T-student test was used to compare between the two groups, with P value <0.05 considered statistically significant.

Results: A total of 24 primigravida (12 participants in respective group) were recruited. Majority of them were Malays (83.3%), and the mean age was 29.38 (+2.81). Most cases were posterior placenta praevia (83.3%) with half of the participants had type 2 praevia (58.3%). PLAT and SERPINE expressions were increased, but not statistically significant in the placental tissue of major placenta praevia compared to non-placenta praevia (controls) (p=0.47 and 0.99). PRAP expression was similar for placenta praevia and non-placenta praevia (p=0.99). TPA and UPA were significantly hypermethylated in placenta praevia compared to controls with p<0.001 respectively.

Conclusions: TPA and UPA were hypermethylated in placental tissue of primigravida with major placenta praevia compared to non-placenta praevia.

Keywords: Methylation, plasminogen activator system, placenta praevia, primigravida