Association between low fetal fraction of cell free DNA and adverse pregnancy outcomes

Abstract

Objective Association between low fetal fraction of cell free DNA and adverse pregnancy outcomes

Study Design This is a secondary analysis of a multicenter prospective cohort study. In 12 different health-care institutions, women with singleton pregnancies were enrolled in early pregnancy and followed up till delivery. The relationship between FF and adverse pregnancy outcomes including preterm labor (PTL), preterm premature rupture of membranes (pPROM), gestational diabetes (GDM) and preeclampsia (PE) was analyzed.

Results A total of 718 women were included in the final analysis. The frequencies of PTL, pPROM, GDM and PE were 1.53%, 4.32%, 5.99%, and 1.39%, respectively. There was no statistically significant difference in mean FF according to the presence or absence of each of adverse pregnancy outcomes (PTL: 8.9 vs 11.3; pPROM: 12.3 vs 11.2; GDM: 10.89 vs. 11.28; PE: 9.8 vs. 11.3; p >0.05, for all). When the study population was classified into 3 groups according to the FF (low FF [< 5th percentile: FF 5.3%], normal FF [5th-95th percentile], and high FF [ >95th percentile: FF 18.36%]), PTL was found more frequently as FF was decreasing (9.7% in low FF vs. 1.2% in normal FF vs. 0% in high FF), which was statistically significant (p< 0.05). Patients with low FF were at risk for PTL, compared to those normal FF (OR 8.63, 95% CI 2.17-34.28). However, there were no differences in the rates of pPROM, GDM and PE according to the degree of FF.

Conclusion Our study shows evidence that low FF is associated with the increased risk of PTL. Further study is needed to determine the clinical significance of low FF and the biological relevance of the findings in this study.