In the modern-day realm of reproductive assessment and treatment, IVF remains as the gold standard fertility therapy for patients wishing to conceive. Nationwide success rates are at an all time high as advancements in the medication protocols, laboratory conditions, and embryo transfer techniques continue to develop and progress. However as with every other treatment course available, IVF too has potential limitations in certain isolated circumstances. The most common such case is that of a “low response”, i.e. when a patient produces very few follicles after stimulation with injectable fertility medications. This scenario leads to very few eggs being retrieved, which corresponds to a lower chance of successfully achieving pregnancy.
As a result, many clinicians have proposed that patients who demonstrate a low response have the IVF procedure itself be cancelled, and the cycle be converted to an intrauterine insemination (IUI) cycle instead. The philosophy is that in this way, the patient can still have a chance at achieving pregnancy following the medication stimulation with an IUI so that the cycle is not lost, and secondly, the egg retrieval is avoided since the likelihood of success is not as high as would have been expected. However this theory is a controversial one, and many reproductive specialists still feel that IVF gives the patient the best prognosis, even with a low response. Dr. John Norian of the National Institute of Child Health and Human Development presented findings at a recent annual meeting of the American Society of Reproductive Medicine that supported this notion of “sticking with” the IVF procedure in cases of low response.
A review of patients at a large private fertility center based in Rockville, Maryland, who were having a first cycle of IVF to IUI conversion was performed. Low response was defined as fewer than four eggs expected at retrieval, and the patients had to have at least one fallopian tube open. A total of 362 patients met this criteria, and they were compared to 407 first time IVF patients who had retrieval of 1 to 3 eggs retrieved during the same time frame. What the researchers found was that the clinical pregnancy rates were significantly higher at 16% in 126 patients who had 2 eggs retrieved, and 24% in 236 patients who had 3 eggs retrieved, as compared to an overall 5% pregnancy rate in patients who were converted to IUI. In the 45 patients with 1 egg retrieved, the pregnancy rate was 2%, which did not differ statistically from the IUI conversion group.
From the above findings, this important study suggests that even when retrieval of only 2 to 3 eggs is expected, patients are still better served in terms of achieving a successful pregnancy by completing the IVF process, and not being converted to an IUI cycle. Certainly with only one egg, then the decision to convert to an IUI cycle can be justified. But until further prospective studies are performed, it appears that if more than one egg is expected to be retrieved, IVF still seems to be the correct way to go.