Furthermore, ZNF831 (zinc finger protein 831) and its loci on chromosome 20q13 were identified as another significant factor in pre-eclampsia. The risk allele rs259983 is also associated with both pre-eclampsia and hypertension, further evidence that the two traits are possibly linked. While the current understanding suggests that maternal alleles are the main hereditary cause of pre-eclampsia, paternal loci have also been implicated. In one study, paternal DLX5 (Distal-Less Homeobox 5) was identified as an imprinted gene. Located on chromosome 7 in the q21 region, DLX5 serves as a transcription factor often linked with the developmental growth of organs. When paternally inherited, DLX5 and its SNP rs73708843 are shown to play a role in trophoblast proliferation, affecting vascular growth and nutrient delivery.Besides specific loci, several important genetic regulatory factors contribute to the development of pre-eclampsia. Micro RNAs, or miRNAs, are noncoding mRNAs that down-regulate posttranscriptional gene expression through RNA-induced silencing complexes. In the placenta, miRNAs are crucial for regulating cell growth, angiogenesis, cell proliferation, and metabolism. These placental-specific miRNAs are clustered in large groups, mainly on chromosomes 14 and 19, and irregular expression of either is associated with an increased risk of an affected pregnancy. For instance, miR-16 and miR-29 are vascular endothelial growth factors (VEGFs) and play a role in upregulating sFLT-1. In particular, the overexpression of miRNA miR-210 has been shown to induce hypoxia, which affects spiral artery remodeling, an important part of the pathogenesis of pre-eclampsia.
Aspirin
Taking aspirin is associated with a 1 to 5% reduction in pre-eclampsia and a 1 to 5% reduction in premature births in women at high risk. The World Health Organization recommends low-dose aspirin for the prevention of pre-eclampsia in women at high risk and recommends it be started before 20 weeks of pregnancy. The United States Preventive Services Task Force recommends a low-dose regimen for women at high risk beginning in the 12th week. Benefits are less if started after 16 weeks.The more recent study ASPRE, besides its efficacy in identifying women suspected to develop pre-eclampsia, has also been able to demonstrate a strong drop in the rate of early pre-eclampsia (-82%) and preterm pre-eclampsia (-62%). The efficacy of aspirin is due to screening to identify high risk women, adjusted prophylaxis dosage (150 mg/day), timing of the intake (bedtime) and must start before week 16 of pregnancy. Physical activity
There is insufficient evidence to recommend either exercise or strict bedrest as preventive measures of pre-eclampsia. Smoking cessation
In low-risk pregnancies, the association between cigarette smoking and a reduced risk of pre-eclampsia has been consistent and reproducible across epidemiologic studies. High-risk pregnancies (those with pregestational diabetes, chronic hypertension, history of pre-eclampsia in a previous pregnancy, or multifetal gestation) showed no significant protective effect. The reason for this discrepancy is not definitively known; research supports speculation that the underlying pathology increases the risk of pre-eclampsia to such a degree that any measurable reduction of risk due to smoking is masked.