OBJECTIVETo study the presence of trophoblast cells in the lower uterus in early pregnancy, identify fetal cells by immunocytochemistry, and determine the best timing for sample collection.

METHODSSamples from healthy gravida in early pregnancy were divided into HE group (I) and immunocytochemistry group (II), and those from healthy nonpregnant women were also divided into HE group (III) and immunocytochemistry group (IV). Four different methods (usage of a cotton swab, aspiration of the cervical mucus, lavage of the endocervical canal, and lavage of the intrauterine cavity) were employed for collecting the samples, which were tested with HE staining or immunocytochemistry, and the presence of fetal cells was observed under optical microscope.

RESULTS AND CONCLUSIONFetal cells were detected in the genital tract of the gravida in early pregnancy. Utilization of the lavage of the endocervical canal or the lavage of the intrauterine cavity allowed greater amount of fetal cell acquisition, and sampling of the fetal cells between 50 days and 79 days of gestational age yielded optimal results. These sampling methods may provide safe and effective means for prenatal diagnosis with minimal invasiveness.