Pregnancy rates of day 4 and day 5 embryos after culture in an integrated time-lapse incubator

Abstract

BackgroundThe aim of this study was to compare pregnancy rates in patients undergoing IVF/ICSI with embryo transfer after 4 and 5 days of culture in a closed incubation system with integrated time-lapse imaging.MethodsOut of n = 2207 in vitro fertilization (IVF)/ intracytoplasmic sperm injection (ICSI) cycles performed between January 2011 and April 2016 at a tertiary referral university hospital, a total of n = 599 IVF/ICSI cycles with prolonged embryo culture in an integrated time-lapse system (EmbryoScope© (Vitrolife)) until day 4 or 5 were retrospectively analyzed with regard to embryo morphology and pregnancy rates.ResultsA transfer on day 5 compared to a transfer on day 4 did not result in higher implantation and clinical pregnancy rates (IR 29.4% on day 4 versus 33.0% on day 5, p = 0.310; CPR 45.2% on day 4 versus 45.7% on day 5, p = 1.0). The percentage of ideal embryos transferred on day 4 was comparable to the rate of ideal embryos transferred on day 5 (41.6% versus 44.1%, p = 0.508). However, on day 4 a significantly higher number of embryos was transferred (1.92 on day 4 versus 1.84 on day 5, p = 0.023), which did not result in higher rates of multiple pregnancies.ConclusionsPregnancy rates in IVF/ICSI cycles with integrated time-lapse incubation and transfer on day 4 and 5 are comparable. This finding provides the clinician, IVF laboratory and patient with more flexibility.Trial registrationThis study was retrospectively registered by the local ethics committee of the University of Heidelberg on December 19, 2016 (registration number S-649/2016).

Should the flexibility enabled by performing a day-4 embryo transfer remain as a valid option in the IVF laboratory? A systematic review and network meta-analysis

“…Thereafter, full texts were screened seeking for ultimately relevant articles, as well as the reference lists of selected relevant publications were assessed for final inclusion. This thorough screening resulted in a total of 15 studies [5,6,8,13,[17][18][19][20][21][22][23][24][25][26][27] that are employed for the present meta-analysis. In Fig.…”

“…Fifteen studies [5,6,8,13,[17][18][19][20][21][22][23][24][25][26][27] reported results on clinical pregnancy rates per ET cycle. Five different study designs (D4 vs. D3; D4 vs. D5; D4 vs. D2/3; D4 vs. D3/5; D4 vs. D2/3/5) comparing a total of four different days including 11,034 ET cycles were evaluated.…”

“…Regarding the number of embryos transferred only studies with two or less embryos transferred were selected for evaluation. Four studies were included in this sensitivity analysis [8,13,18,20] reporting on the primary outcome of this metaanalysis, namely clinical pregnancy rate. Two different study designs (D4 vs. D3/5 and D4 vs. D5) comparing three different days including a total of 2974 cycles were evaluated.…”

“…Traditionally, the ET process was carried out 1 or 2 days following fertilization, establishing cleavage stage ET as the norm [8]. The main reason behind this was the inadequate laboratory culture conditions, in line with the poorer culture media components, that failed to provide a proper environment for the extended development of the embryos.…”

“…The advent of sequential culture media undoubtedly represents a determinant factor that challenged the previous practice. The wide pallet of components successfully sustains extended embryo culture, driving specialists to adopt blastocyst transfer with safety [2,8]. The first major wave of the embryonic genome activation is noted on D3 between the four-and eight-cell stage, although the initial expression of the first paternal mRNAs occurs on D2 during the three-to four-cell stage [12].…”