Figure 2.

Relationship between fetal fraction and maternal BMI. A. BMI was negatively correlated with fetal fraction in sequencing of shorter cfDNA for NIPT. B. In pregnant women with the same body mass index range, fetal fraction decreased with longer cfDNA fragment size. In the same cfDNA fragment size range, fetal fraction decreased with maternal BMI. C. The mean fetal fractions for maternal BMI < 18.5, 18.5-24.9, 25-30, and ≥ 30 kg/m² were 33.7%, 31.4%, 27.5%, and 22.2%, respectively. The fetal fraction in obese pregnant women decreased significantly; however, the fetal fraction was > 10% in 96.3% of pregnant women by sequencing of short cfDNA NIPT. D. The mean fetal fraction was 3.4% at first sampling, 4.73% at repeat sample collection (mean interval 11 days), and 15.48% when sequencing of shorter cDNA NIPT (mean size of cell free DNA: 125 bp). E. The average increased times were 1.39 and 2.35 at repeat sample collection and shorter cfDNA sequencing, respectively.