Detection of fetal DNA in the peritoneal cavity during pregnancy.

There is increasing evidence that fetal cells are commonly shed toward the cervix and in maternal circulation during pregnancy. In this study, a sample of peritoneal fluid was retrieved from a primigravida at 12 weeks' gestation undergoing urgent intervention for the torsion of an adnexal mass; the sample was then analysed by a polymerase chain reaction (PCR) assay using primers for X- and Y-chromosome specific sequences, and Y-derived sequences were identified. The course of pregnancy was then uneventful until term, when the patient delivered a male fetus, thus, supporting the hypothesis of a fetal origin for the Y-derived sequences detected in the peritoneal fluid. Further studies are required in order to confirm these findings and precisely define the origin of these sequences; however, this report seems to provide further evidence of the spreading of fetal cells during gestation and addresses relevant issues as to the possibility of collecting these cells by culdocentesis and intraperitoneal lavage for prenatal diagnosis.