Single-needle insertion: an alternative technique for early second-trimester genetic twin amniocentesis.

Single-needle insertion as an alternative technique for genetic amniocentesis in twin gestation has been evaluated in 27 pregnancies. A 22-gauge needle was inserted into the most proximal sac and amniotic fluid was aspirated. The needle was then traversed through the dividing membrane to enter the second sac and amniotic fluid was aspirated. This technique avoids the use of dye and ensures tapping of both sacs. No fetal losses attributable to the procedure occurred during the trial. In comparison with the double-needle insertion, it is a swift and easy procedure and reduces discomfort to the patient.