OBJECTIVE: If noninvasive prenatal testing using next generation sequencing is to be effective for pregnant women, a cell-free fetal DNA (cffDNA) fraction above 4% is essential unless the depth of sequencing is increased. This study's objective is to determine whether physical activity has an effect on the proportion of cell-free DNA (cfDNA) arising from the fetus (fetal fraction). METHODS: Nine pregnant women carrying male fetuses at gestational age 12(+0) weeks to 14(+6) weeks were included. Plasma from nine pregnant women was drawn prior to, immediately after, and 30 min after 30 min of cycling with a pulse-rate of 150 beats per minute. The concentrations of cffDNA (DYS14) and cfDNA (RASSF1A) were assessed using quantitative real-time polymerase chain reaction. RESULTS: The fetal fraction decreased significantly in all participants after physical activity (p < 0.01), a decrease varying from 1-17 percentage points. This was due to a significant increase in the concentration of cfDNA (p < 0.01), whereas the concentration of cffDNA remained the same. This alteration of the fetal fraction was not present 30 min after physical activity. CONCLUSION: When planning the timing of noninvasive prenatal diagnosis based on the fetal fraction, physical activity prior to sampling should be avoided.
Prenatal Diagnosis, 2014, Vol 34, Issue 4, p. 341-4