Lubricant Gel Versus Sterile Water for Speculum Insertion During Embryo Transfer: a Randomized Non-inferiority Clinical Trial

In vitro fertilization (IVF) involves a highly complex series of events leading to the creation of an embryo. The transfer of that embryo, the final step in the process, is seen as a critical moment at the culmination of this incredibly intricate process. The technique of the embryo transfer (ET) has undergone a slow evolution, but for many physicians, this step remains relatively consistent throughout years of practice. While the procedure itself is relatively short, physicians often have specific preferences for each of the steps involved, either supported by evidence, learned from mentors or guided by experience and individual success. As such, ET success rates are a statistic that generates significant pride among physicians and are often tracked by clinics as a quality control metric. Interestingly, there are significant outcome differences between physicians.

Numerous techniques and practices employed during ET have been studied. For some, the evidence is robust, while for others, it is very limited. Some practices and techniques were found to improve ET success, such as: abdominal US guidance, removal of cervical mucus, use of a soft catheter, and placement of the embryo at a distance of more than 10 mm from the uterine fundus. For other aspects of ET there is no sufficient evidence to decide on the preferred practice. These include the optimal length of the procedure and rotation of the catheter during withdrawal. Good-quality randomized clinical trials are much needed in order to decide on the best practice. For example, there was previously a concern that the use of powdered gloves during ET might be toxic to the embryos. However, a single RCT (n=712) has shown that using powdered gloves resulted in similar pregnancy rates compared to unpowdered gloves.

Lubrication gels are widely used in numerous gynecologic procedures in order to ease the insertion of speculum and visualize the cervix. It was shown that applying lubricating gels significantly decreases patient pain during vaginal speculum examination. While many fertility specialists use lubrication gels to insert the speculum during ET, others are strongly reluctant to use gels due to concern that they might have a detrimental effect on embryos and ET success. Similar concern was prevalent regarding the use of lubrication gel during Pap-smear for detection of cervical dysplasia. However, several studies have shown that the use of small amount of water-soluble gel does not change cervical cytology. Lubrication gels might have deleterious effect on sperm motility. However, there wasn't any study examining the effect of lubricant gel on ET success.

The investigators hypothesize that using a lubrication gel will not reduce the live birth rate per transfer, but decrease patient pain during procedure.