Optimizing the Technique of Embryo Transfer in IVF Using Better Imaging Guidance

Fertilization in Vitro

This trial seeks to improve ultrasound imaging during embryo transfer in IVF by using a small, high resolution ultrasound probe used routinely for cardiac imaging in children.

Since the first pregnancy using IVF was achieved nearly 40 years ago, many aspects of this procedure have undergone significant progress. In contrast, the technique of embryo transfer (ET) has remained relatively unchanged. A simple yet critical element in the final step of IVF, ET has received little attention. In general, the procedure starts by placing a speculum in the vagina to visualize the cervix, which is cleansed with saline solution or culture media. A transfer catheter is loaded with the embryos is inserted through the cervical canal and advanced into the uterine cavity where the embryos are deposited. The catheter is then withdrawn and handed to the embryologist, who inspects it for retained embryos. Ultrasound (US) guidance is used to facilitate atraumatic insertion of the catheter, as well as ensure correct location in the uterine cavity. The available evidence suggests that there is a benefit of using US guidance during ET (Teixeira et al, Ultrasound Obstet Gynecol. 201;45:139-48, Abou-Setta et al, Fertil Steril. 2007;88:333-41). High quality US imaging is difficult to achieve if the distance from the abdominal wall to the uterus is big (thick abdominal wall, retro-verted uterus), or if the bladder is not full enough. High resolution US imaging dictates short distance between the US transducer and the organ of interest (in our case cervical canal and endometrium). Previous effort in that direction was done using a vaginal US probe. However, this instrumentation makes the ET technique cumbersome and difficult to perform. We hypothesize that a significant advantage in imaging quality can be achieved by placing a flat or concave high frequency US transducer in the posterior fornix as an extension of the posterior speculum blade. Our overarching goal is to develop new ET procedure; this procedure will be dependent on precise and high resolution imaging. For that goal we consulted with ultrasound experts that recommended the use of dedicated probe. After a thorough review we found a probe (Philips 21381A / T6207) that is used for pediatric transesophageal applications with operating frequency of 4-7 Megahetz. As part of the embryo transfer, the investigators plan to insert the above probe into the posterior fornix. The investigators will then evaluate the visualization abilities of placing a probe closer to the uterus. The aim is to define the ultrasound image parameters for ET. The information will be used to define the technical specification for a tailor made ET probe.

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