P-263 Increased live birth rate, blastocyst formation and quality when embryos were cultured in EmbryoScope time-lapse incubators compared to MINC™ benchtop incubators
Authors: Lee L , Kelley R , Stevens J , Gardner D 
Published: June 2023

Abstract

Study question
Does embryo culture using the EmbryoScope or EmbryoScope+ time-lapse incubators affect blastocyst development and birth rate compared to MINC™ benchtop incubators?

Summary answer
Culture in the EmbryoScope or EmbryoScope+ resulted in higher blastocyst quality and utilisation rates, and birth rates from fresh blastocyst transfers was increased.

What is known already
Time-lapse incubators enable continuous monitoring of embryos so that morphological changes can be observed, and embryo selection software applied to select the best embryo for transfer. However, there has been considerable debate over the benefits of such systems and a review of 8 randomized controlled trials (Armstrong et al., 2019; Cochrane Database Syst Rev (5)) was inconclusive. Interpretation and comparison of results are complicated by differences among imaging systems and variations in culture protocols between clinics. EmbryoScope time-lapse incubators may also have better temperature and pH stability than benchtop incubators, improving embryo development.

Study design, size, duration
Retrospective data from 1189 cycles in the EmbryoScope or EmbryoScope+ and 1381 MINC cycles conducted concurrently in the same laboratory over 18 months. All embryos from each patient cycle were cultured in one incubator type. All patients from a treating clinician were allocated to one incubator type.

Participants/materials, setting, methods
All IVF/ICSI cycles from a single clinic. Cycles with vitrified eggs or embryos were excluded. Embryos were cultured in Vitrolife G-TL media under 5% O2, media was refreshed on Day 5. Embryos were scored using the Gardner grading system. For embryos cultured in the Embryoscope, selection of embryos for transfer was based on a combination of Gardner grading and the KIDScore D5 v2 algorithm.

Main results and the role of chance
There was an increase in Day 5 top quality blastocysts (AA) from embryos in the Embryoscope compared to the MINC (15.3% vs.9.7%, p &lt; 0.0001), and Day 5 good quality blastocysts (≥BB, 24.4% vs.16.9%, p &lt; 0.0001). Overall, the utilisation rate was significantly higher from embryos in the Embryoscope (51.3% vs.46.0%, p &lt; 0.0001). From fresh single blastocyst transfers, there was a significant increase in detection of fetal heart by ultrasound (34.7% vs 28.0% p &lt; 0.01) and live birth rate (30.9% vs 24.6%, p&lt;0.01) from embryos cultured in the Embryoscope (n = 972) compared to the MINC (n = 633).
Interestingly, pronuclei were not observed during fertilisation assessment for 84 embryos that subsequently formed blastocysts cultured in the MINC, compared to only 4 embryos in the Embryoscope, suggesting that continuous monitoring increases accuracy in determining fertilisation.

Limitations, reasons for caution
Assessment using the EmbryoViewer compared to an inverted microscope may result in discrepancy in blastocyst grades. The use of KIDscore combined with Gardner grading for embryo selection in the Embryoscope but not the MINC may influence transfer outcomes. As data was collected retrospectively, patients were not randomised to incubator types.

Wider implications of the findings
Culture in the Embryoscope increases the frequency of high-quality usable blastocyst development when compared to a MINC. Importantly, this translates to a higher pregnancy rate and live birth rate from fresh embryo transfers. This may be due to the microwell dishes, incubator performance, embryo selection or all of these.

Trial registration number
Not applicable