High levels of fetal DNA are associated with increased risk of spontaneous preterm delivery

Abstract

Objective: To assess whether spontaneous preterm delivery can be predicted from the amount of cell free fetal DNA (cffDNA) as determined by routine fetal RHD genotyping at 25 weeks' gestation.

Study design: Cohort study including RhD negative women participating in a routine RHD screening programme. A standard dilution curve was used to quantify the amounts of cffDNA. Values above the 95(th) centile for the study population defined high levels of cffDNA.

Results: We found a highly significant association between preterm delivery and cffDNA levels above the 95(th) centile (p = 0.002). Using logistic regression, women with high levels of cffDNA had an odds ratio of 6.3 (95% confidence interval: 1.9-20.9) for preterm delivery before 37 weeks and an odds ratio for delivery before 34 weeks of 16.6 (95% confidence interval: 3.2-84.7) when adjusting for gestational age at sampling, body mass index and previous miscarriages/terminations of pregnancy.

Conclusion: High levels of cffDNA at 25 weeks are associated with increased risk of spontaneous preterm delivery.