First-trimester endocervical irrigation: feasibility of obtaining trophoblast cells for prenatal diagnosis

We sought to determine the feasibility of obtaining trophoblast cells for first-trimester prenatal diagnosis using endocervical irrigation. We studied 20 pregnant patients between 7-10.5 weeks' gestation who presented for elective pregnancy termination. Under ultrasound guidance, a specially designed plastic catheter was advanced to the level of the internal cervical os. Gentle flushing and aspiration was performed with 3 mL of normal saline. The material obtained was fixed and stained. A placental pathologist identified trophoblast cells using light microscopy. In another five cases, we attempted to culture the endocervical washings. Trophoblast cells were identified by microscopy after staining the cultured material with an anti-alpha-hCG-antibody bound stain. In ten of 20 cases (50%), trophoblast material was retrieved on irrigation. Of the five additional cases on which culture was attempted, trophoblast was successfully cultured in one, the results were equivocal in two, and culture was unsuccessful in the other two. Trophoblast cells for prenatal diagnosis can be obtained in a significant percentage of cases by first-trimester endocervical irrigation. The advantages of irrigation include technical simplicity, brief duration (less than 3 minutes), and suitability to first-trimester diagnosis. Further testing is necessary to determine the risks.