Persistent elevation of cell-free fetal DNA levels in maternal plasma after selective laser coagulation of chorionic plate anastomoses in severe midgestational twin-twin transfusion syndrome.
OBJECTIVE
This study was undertaken to determine whether laser thermocoagulation for twin-twin transfusion syndrome (TTTS) causes increased cell-free fetal DNA levels in maternal plasma, potentially as a result of placental injury.


METHODS
We enrolled 34 patients with twin pregnancies complicated by severe TTTS who underwent fetoscopic selective laser ablation of placental vascular anastomoses. Blood samples were drawn before and sequentially after the procedure. Fetal DNA in maternal plasma was quantified by polymerase chain reaction amplification of a Y-chromosome sequence.


RESULTS
Compared with baseline, median elevations of fetal DNA levels were 0.8% at 30 minutes ( P = .32), 15.8% at 60 minutes ( P = .1), 179.5% at 24 hours ( P = .003), and 172.9% at 48 hours ( P = .003). Factors associated with increased fetal DNA levels at 24 hours after procedure included longer operation time, higher number of vessels ablated, and subsequent in utero fetal death ( P = .01, .04, and .04, respectively).


CONCLUSIONS
Persistent elevation of fetal DNA levels in maternal plasma after laser ablation suggests that circulating fetal DNA could derive from placental injury. Plasma fetal DNA analysis may be an additional prognostic marker for fetal outcome after laser therapy.
Wataganara
Tuangsit
T
Division of Genetics, Department of Pediatrics, Obstetrics and Gynecology, Tufts-New England Medical Center, Tufts University School of Medicine, Boston, Mass, USA.
Gratacos
Eduard
E
Jani
Jacques
J
Becker
Jorge
J
Lewi
Liesbeth
L
Sullivan
Lisa M
LM
Bianchi
Diana W
DW
Deprest
Jan A
JA
D004247:DNA / Q000097:blood*; D005260:Female; D005330:Fetofetal Transfusion / Q000601:surgery*; D005333:Fetus / Q000378:metabolism*; D006801:Humans; D017075:Laser Coagulation; D008297:Male; D010920:Placenta / Q000473:pathology*; D011247:Pregnancy / Q000097:blood*
D004247:DNA