Embryo transfer media and catheters

Abstract

An embryo transfer catheter is a special equipment that’s designed and manufactured to ensure safe deposition of human embryos generated in the embryology laboratory to the endometrial cavity. As such, they undergo several tests of embryo toxicity before being marketed. The vast majority of currently available embryo transfer sets consist of two parts: An outer sheath and the inner catheter proper. While the first is used to negotiate the cervical canal, the embryos are loaded into the inner catheter, which is then introduced to the endometrial cavity through the lumen of the former. Embryo transfer catheters are defined by several features. These include material, malleability and shape of the outer sheath, stiffness and echogenicity of the inner catheter. Several randomized controlled trials have demonstrated that a soft catheter yields better clinical results compared to a stiff embryo transfer catheter. More recent models with a pre-curved outer sheath and a bulb tip seem to facilitate the negotiation of the cervical canal without compromising the clinical outcome. While catheters with increased echogenicity are better visualized during the transfer procedure, the clinical outcome is not improved. According to the available data, hyaluronan- enriched transfer medium can improve the clinical outcome, especially in patients with poor prognostic features.