As patients who endure the challenges of IVF know all too well that there are literally dozens of factors that contribute to the success of a given cycle, all of which culminate and converge on the embryo transfer. After dozens of injections, multiple blood draws, countless vaginal ultrasounds, and the egg retrieval, the embryo transfer procedure can feel sort of anti-climactic at times. However, there is evidence that transfer technique can influence the chance of achieving a pregnancy and a live birth, and that ultimately live birth rates vary by the doctor who is performing the transfer.
Doctors do many things to make sure the embryo is delivered to the right location and to ensure that it stays there. These include giving medications like progesterone to prevent small uterine contractions and using ultrasound to visualize the location of the transfer catheter during the procedure. Strong evidence also suggests that using soft transfer catheters and ultrasound guidance improve the chance of a successful transfer.
We at Reproductive Medicine Associates of New Jersey – a large academic private practice, which performs a large number of single blastocyst transfers after PGS – wanted to perform a study that determined how much the chance of achieving pregnancy and a live birth was influenced by the physician performing the transfer. To do so, we examined 2,707 embryo transfers performed by 11 doctors over a five-year period (2011 to 2015). To attempt to isolate the impact of the transferring doctor on the likelihood of success, we only considered the transfer of chromosomally normal embryos (as determined by PGS).
After controlling for a number of other factors, we observed that there was a significant difference in the likelihood of achieving pregnancy between the lowest performing doctor and the highest performing doctor. We observed that embryos transferred by the lowest performer resulted in a successful implantation 61.7% of the time, while the highest performer achieved implantation 73.5% of the time. More importantly, the possibility of achieving a live birth was also significantly different between the lowest and highest performer (50.6% vs. 66.4%).
So what does this mean for patients as they consider the many different offices and practice settings available? You obviously want to optimize every detail of your treatment cycle to give you the best chance of success. So, with the knowledge that embryo transfer technique does matter, are you better off pursuing care at a smaller clinic where you absolutely know which doctor will be performing your transfer? Or, are you better off at a bigger clinic with multiple doctors hoping that you end up with the highest performer?
The answer to this question is complicated. It is possible that smaller clinics are staffed by one or two doctors who excel at embryo transfer. However, it is equally likely that the transferring doctor at a solo practitioner clinic is well below average. The same possibilities exist in larger clinics with rotating schedules of “transfer doctor of the day.” Not every patient will be scheduled on the day that the top performer is in the office. However, one advantage of larger clinics who do internally track their success rates, is that comparatively high-achieving doctors can be identified and the factors that contribute to their success rates can be characterized. With this in mind, some practices have even videotaped the ultrasound image of the transfer procedure (with patients’ consent) to isolate the most important aspects of the high-performing doctors’ technique. The idea in this practice setting is that a rising tide will lift all boats.
In general, the embryo transfer success rates per doctor are not available to patients, as there is no regulatory requirement for offices to report these numbers. However, clinics who do track these indicators may have internal data available and it never hurts to ask for it. That being said, as was mentioned at the beginning of this post, a multitude of factors contribute to the likelihood of achieving pregnancy and delivering a healthy baby in a given cycle, and the embryo transfer procedure is just one of these.
Reviewing variation in success rates internally can be a painful reminder to individual doctors that we must be thoughtful about all aspects of fertility care. It’s often even more challenging to share these things in a public forum – like a national meeting or a publication. However, the hope at RMANJ is that being honest and forthright about variation in physician transfer success will not only improve the outcomes of the patients in our practice through honest self-assessment, but hopefully spur a wider discussion about the importance of quality control in general.