The Number of Endovascular Trophoblasts in Maternal Blood Increases Overnight and after Physical Activity: An Experimental Study.
BACKGROUND
Fetal cells in maternal blood may be used for noninvasive prenatal diagnostics, although their low number is a challenge. This study's objectives were to evaluate whether physical activity, transabdominal and transvaginal ultrasound scans of the uterus, as well as overnight or day-to-day variation affect the number of isolated fetal cells, more specifically the presumed endovascular trophoblast (pEVT).


METHODS
In each of 3 different experiments, 10 normal singleton pregnant women (gestational age 10+4-14+4 weeks) participated. The number of pEVTs was assessed in 30-36 ml blood using specific markers for enrichment and identification.


RESULTS
The number of pEVTs increased overnight (p = 0.001) from a median of 1.5 to 3.5 and even further to a median of 6.0 after 30 min of physical activity (p = 0.04) but was not affected by transabdominal and transvaginal ultrasound scans. Repeated sampling showed that the interindividual variation of pEVTs was higher than the intraindividual variation (p < 0.001). However, even in pregnant women with a consistently low number of pEVTs, isolation of the pEVTs for prenatal diagnoses was possible in all cases by doing 2 separate blood samplings a few days apart.


CONCLUSIONS
The number of pEVTs identified in maternal blood can be increased by presampling conditions or repeated sampling.
Department of Obstetrics and Gynecology, Aarhus University Hospital, Skejby, Aarhus, Denmark.
Jacob Mørup
JM
Schlütter
Ida
I
Kirkegaard
Anne Sigaard
AS
Ferreira
Lotte
L
Hatt
Britta
B
Christensen
Steen
S
Kølvraa
Niels
N
Uldbjerg
D002940:Circadian Rhythm; D015444:Exercise; D005260:Female; D005333:Fetus / Q000166:cytology*; D006801:Humans; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods; D014327:Trophoblasts / Q000166:cytology*