Embryo transfer is the final and perhaps most critical step in determining IVF outcome. Indeed, it has been estimated that poor ET technique may account for many IVF failures—perhaps up to 30% of unsuccessful cycles [3]. It is generally recognised that the skill of the clinician performing ET is more important than catheter type or day of transfer, although most ETs in IVF are done as one procedure where the uterine cavity receives all cultured embryos from a single catheter at the same time. However, recent work has suggested that a two-stage ET specifically for patients with prior IVF failure can yield significantly higher pregnancy rates compared with those having traditional one-step ET [4, 5]. Which ET procedure resulted in the ongoing singleton pregnancy cannot be known with certainty in our patient, but since allied research has suggested that performing an endometrial biopsy prior to actual transfer induces a favourable endometrial response [6], we speculate that our patient’s viable pregnancy may be a continuation of the blastocyst transfer.
In this report, we confirm the effectiveness of coordinated two-stage transfer in a single cycle. Considerable multi-centre data have shown that offering extended in vitro culture and blastocyst transfer, whenever possible, can provide significantly improved pregnancy rates compared with traditional day-3 transfer [7, 8]. Day-3 transfer can still be appropriate for some patients, but there are no reliable guidelines available to prospectively identify which patients would benefit from each treatment approach [9]. Anticipating blastocyst transfer for every IVF patient is inappropriate and risks cycle cancellation due to culture failure, although we are unaware of any published data identifying unsuccessful blastocyst culture as a specific stressor causing patients to abandon IVF. Nevertheless, patient education and counselling are a crucial component of the pre-treatment programme for IVF. Although blastocyst transfer is generally favoured at our institution, day 3 transfers are still performed when clinically indicated. Very few IVF patients get both in the same treatment cycle, however. The current case illustrates a plan tailored to meet the disparate physiological needs of very different embryos, and presents the first published report of a delivery in Ireland after sequential ETs. Additional studies are underway to evaluate this treatment approach for other couples referred for prior IVF failure.