Incubator type affects human blastocyst formation and embryo metabolism: a randomized controlled trial.

STUDY QUESTION: Does the type of incubator used to culture human preimplantation embryos affect development to the blastocyst stage and alter amino acid utilization of embryos in assisted reproduction? SUMMARY ANSWER: Culturing embryos in a time lapse system (TLS) was associated with a higher Day 5 blastocyst formation rate and altered amino acid utilization when measured from Day 3 to Day 5 compared to the standard benchtop incubator. WHAT IS KNOWN ALREADY: Culture environment is known to be important for the developing preimplantation embryo. TLSs provide a stable milieu allowing embryos to be monitored in situ, whereas embryos cultured in standard benchtop incubators experience environmental fluctuations when removed for morphological assessment. STUDY DESIGN, SIZE, DURATION: A prospective clinical trial randomizing 585 sibling embryos to either the TLS (289 embryos) or the standard benchtop incubator (296 embryos) over a 23-month period in a UK University Hospital Fertility Clinic. PARTICIPANTS/MATERIALS, SETTING, METHODS: Participants were aged 42 years or under, had an antral follicle count of ≥12 and ≥6 2 pronucleate zygotes. Zygotes were cultured individually in 25 µl of medium. Randomized embryos were graded and selected for transfer or cryopreservation on Day 5. For those embryos produced by women who underwent stimulation with recombinant FSH injections and were triggered with hCG, spent medium was collected on Day 5 for amino acid analysis by high pressure liquid chromatography. Clinical pregnancy was defined as the presence of a foetal heart beat on ultrasound scan at 7 weeks. MAIN RESULTS AND THE ROLE OF CHANCE: Overall, blastocyst formation rate on Day 5 was significantly higher in embryos cultured in the TLS (55%) compared to the standard incubator (45%; P = 0.013). Similarly, there was an increase in the number of blastocysts suitable for cryopreservation in the TLS (31%) compared to the standard incubator (23%; P = 0.032). There was a significant difference in the utilization of 12 amino acids by blastocysts cultured from Day 3 to Day 5 in the TLS compared to the standard incubator. Embryos cultured in the TLS displayed an increased total amino acid utilization (P < 0.001) and reduced amino acid production (P < 0.001) compared to those in the standard incubator. Irrespective of incubator used, embryos fertilized by ICSI depleted significantly more amino acids from the medium compared to those fertilized by conventional IVF. There was no difference in the mean score of blastocysts transferred, or the clinical pregnancy rate after transfer of embryos from either of the incubators. LIMITATIONS, REASONS FOR CAUTION: The study was not powered to discern significant effects on clinical outcomes. WIDER IMPLICATIONS OF THE FINDINGS: The metabolism and development of preimplantation embryos is impacted by the type of incubator used for culture. Further research is required to investigate the long-term implications of these findings. STUDY FUNDING/COMPETING INTEREST(S): NIHR Southampton Biomedical Research Centre Commercial and Enterprise Incubator Fund funded this study. The TLS was provided on loan for the study by Vitrolife. The authors declare no conflict of interests. TRIAL REGISTRATION NUMBER: ISRCTN73037149. TRIAL REGISTRATION DATE: 12 January 2012. DATE OF FIRST PATIENT'S ENROLMENT: 21 January 2012.

The Fatty Acid Composition of Human Follicular Fluid Is Altered by a 6-Week Dietary Intervention That Includes Marine Omega-3 Fatty Acids.

The fatty acid composition of human follicular fluid is important for oocyte development and for pregnancy following in vitro fertilization (IVF). This study investigated whether a dietary intervention that included an increase in marine omega-3 fatty acids, olive oil and vitamin D alters the fatty acid composition of human follicular fluid. The association of lifestyle factors with follicular fluid fatty acid composition was also investigated. Fifty-five couples awaiting IVF were randomized to receive the 6-week treatment intervention of olive oil for cooking, an olive oil-based spread, and a daily supplement drink enriched with vitamin D and the marine omega-3 fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) and 56 couples were randomized to receive placebo equivalents. Dietary questionnaires were completed, and samples of blood were taken before and after the intervention. Follicular fluid was collected at oocyte retrieval and the fatty acid profile assessed using gas chromatography. In the control group, individual fatty acids in red blood cells and follicular fluid were significantly correlated. Furthermore, a healthier diet was associated with a lower percentage of follicular fluid arachidonic acid. The follicular fluid of women in the treatment group contained significantly higher amounts of EPA and DHA compared to the control group, while the omega-6 fatty acids linoleic, γ-linolenic, dihomo-γ-linolenic, and arachidonic were lower. This is the first report of a dietary intervention altering the fatty acid composition of follicular fluid in humans. Further research is required to determine whether this intervention improves oocyte quality.

Effect of a 6-week "Mediterranean" dietary intervention on in vitro human embryo development: the Preconception Dietary Supplements in Assisted Reproduction double-blinded randomized controlled trial.

OBJECTIVE: To study the impact of increased dietary intake of omega-3 fatty acids, vitamin D, and olive oil for 6 weeks before in vitro fertilization (IVF) or IVF-intracytoplasmic sperm injection (ICSI) on morphokinetic markers of early embryo development. DESIGN: A double-blinded randomized controlled trial. SETTING: Academic IVF unit. PATIENT(S): A total of 111 couples undergoing IVF or IVF-ICSI were recruited. INTERVENTIONS(S): Fifty-five couples received the 6-week study intervention of a daily supplement drink enriched with omega-3 fatty acids and vitamin D plus additional olive oil and olive oil-based spread, and 56 couples received the control intervention. MAIN OUTCOME MEASURE(S): The primary end point for the study was the time taken for completion of the second cell cycle after fertilization (CC2). Secondary end points included time to complete the third and fourth cell cycles (CC3 and CC4), the synchrony of the second and third cell cycles (S2 and S3), and the day 3 and day 5 Known Implantation Data Scores (KIDScores). RESULT(S): There was no difference in CC2 between the two groups. However, CC4 was accelerated in the study group compared with the control group, and a significantly shortened S3 as well as an increase in KIDScore on day 3 were observed, indicating improved embryo quality in the study group. CONCLUSION(S): This study demonstrates that a short period of dietary supplementation alters the rate of embryo cleavage. Further research is required to investigate the mechanisms that regulate this effect, and whether the impact on embryo development translates into improved clinical outcomes. CLINICAL TRIAL REGISTRATION NUMBER: ISRCTN50956936.