A new technique is described for amniocentesis in twins. Using a curvilinear or linear transducer, the separating membrane and an adjacent pocket of amniotic fluid in each cavity are simultaneously visualized. An amniocentesis needle is advanced into the first cavity. A second needle is introduced into the other amniotic cavity without altering the position of the transducer. This technique permits visualization of both needles simultaneously, providing proof of proper placement of the needle in each cavity. The advantages are unambiguous evidence of correct sampling of each cavity and lack of necessity for injection of a foreign substance into the amniotic sac. Finally, hard-copy documentation of proper needle placement is generated for the records. This procedure has been performed in seven twin sets with good results and patient acceptance.
(C) 1992 The American College of Obstetricians and Gynecologists