Maternal smoking: effect on circulating cell-free fetal and total DNA levels in maternal plasma from the second trimester.
OBJECTIVE
To estimate whether potential clinical applications of cell-free fetal and total DNA in the field of noninvasive prenatal diagnosis need to be adjusted for maternal smoking status.


METHODS
In this study, using 344 maternal blood samples from the second trimester of pregnancy, circulating cell-free DNA in maternal plasma samples, specific for the SRY and DYS14 loci (representing fetal DNA) and GAPDH sequence (representing total genomic DNA) were quantified by real-time polymerase chain reaction.


RESULTS
Fetal sex determination was 100% accurate using a combination of probes for SRY and DYS14. The levels of DYS14 and SRY detected were significantly correlated (r=0.884, P<.001). No significant difference was seen between the quantitative levels of cell-free male fetal DNA between the smoking groups and control group. Similarly, no significant difference was seen in the amount of total cell-free DNA in the study population.


CONCLUSIONS
In contrast to first- and second-trimester screening assays for Down syndrome, where smoking status significantly affect levels of maternal serum analytes, smoking status does not affect quantitative levels of cell-free fetal DNA or total cell-free DNA in maternal plasma.


METHODS
II.
University of Basel, Department of Obstetrics and Gynecology, Basel, Switzerland.
Olav
O
Lapaire
Thorsten
T
Volgmann
Dorothy
D
Huang
Sinuhe
S
Hahn
Wolfgang
W
Holzgreve
Xiao Yan
XY
Zhong
D000328:Adult; D015415:Biomarkers; D016022:Case-Control Studies; D004247:DNA / Q000032:analysis* / Q000097:blood; D015342:DNA Probes; D005260:Female; D005333:Fetus; D024282:Genes, sry; D006801:Humans; D008431:Maternal-Fetal Exchange / Q000235:genetics*; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011296:Prenatal Diagnosis / Q000379:methods*; D015203:Reproducibility of Results; D012732:Sex Determination Analysis / Q000379:methods*; D012907:Smoking / Q000097:blood*
D015415:Biomarkers; D015342:DNA Probes; D004247:DNA