Objective: To evaluate the potential link between serum LH concentrations on the day of oocyte triggering and pregnancy outcome during controlled ovarian hyperstimulation. Materials and Methods: In this retrospective cross-sectional study, data of women ≤42 years undergoing fresh embryo transfer cycles and who had downregulated with GnRH antagonist protocol in a 12-month period was reviewed. Patients with incomplete hospital records were excluded. Women were divided into four groups based on the percentiles of the serum LH level on the day of oocyte triggering: <1.49 (<25 th percentile), 1.49–2.59 (25–50 th percentile), 2.60–4.60 (50–75 th percentile), and >4.60 IU/L (>75 th percentile). Clinical pregnancy was considered the primary outcome, while chemical pregnancy and implantation rate were the most important secondary outcomes which were compared between the four groups. Results: Four hundred and nighty-three women of 1003 infertile women, who were initially assessed for eligibility, met the inclusion criteria. Finally, 426 women were analyzed. Levels of progesterone were significantly correlated with the level of LH on the day of trigger in the >4.60 IU/L group ( r = 0.20, P = 0.034). Furthermore, the levels of estradiol were significantly correlated with the level of LH on the day of trigger in the <1.49 IU/L ( r = 0.21, P = 0.026). The number of retrieved oocytes, 2PNs (two pronucleis), number, and quality of total embryos were similar between groups ( P > 0.05). With regard to oocyte maturity rate, fertilization proportion, fertilization rate, chemical pregnancy rate, and clinical pregnancy rate, there was no difference between varied LH levels in the four groups ( P > 0.05). The only observed difference was the implantation rate that was significantly higher in the 2.60–4.60 IU/L group than the <1.49 IU/L group ( P < 0.05). Conclusions: Our result could not show the potential link between LH concentrations during GnRH antagonist cycles and pregnancy outcomes. However, very low LH levels during ovarian stimulation period may negatively affect the implantation rate.

Embryo incubation and evaluation are critical steps in assisted reproductive technology (ART). Conventionally, embryo assessment has been done by embryologists through removing embryos from a conventional incubator during the culture period. Over recent years, time-lapse systems (TLS) have been established which can take digital images of embryos at key points and time intervals. This technique allows embryologists to assess the embryo quality in the steady culture environment. According to TLS studies and prepared algorithm models, it seems that TLS alone or in combination with conventional morphology can be considered as a useful diagnostic tool to determine high-quality embryos and improve embryonic implantation and pregnancy rates. In addition, there were remarkable diferences between embryo developmental time points and intervals regarding embryo gender, embryo fragmentation, and type of ovarian stimulation protocol. For conident conclusion, time-lapse imaging should be evaluated in further studies, and the system should be evaluated for cost/beneit ratio efectiveness in individual laboratory.Keywords: embryo cleavage, embryo morphokinetics, embryoscope, time-lapse imaging IntroductionAssisted reproductive technology (ART) may help infertile couples to realize their dream to have a child in their family, but pregnancy and live birth rates following in vitro fertilization (IVF) still remain low. It is ideal to identify viable embryos with the highest implantation potential to raise IVF success rates. In the traditional IVF practice, embryo assessments are mainly based on the morphologic observation and grade of embryologists at each stage of oocyte and embryonic development. Some features including oocyte and embryo quality, blastomere numbers and regularity, the percentage of fragmentation, and cytoplasmic granularity have been deined as prognostic indicators of successful pregnancy. This traditional embryo assessment method may have some detrimental efects on embryo growth because frequently opening and closing of incubators often cause to the change of embryo culture environmental steadiness. In order to reduce the inter-and intra-observer diference change, the time-lapse imaging (TLI) has been introduced into in vitro fertilization (IVF) laboratory. The application of time-lapse technology to the clinical IVF laboratory has supported more detailed observations on the embryo development researches quickly.The aim of this chapter is to determine whether TLI is useful for selection of "top quality" embryos for transfer to improve ART outcome rather than conventional morphological evaluation. The possible correlation between embryos' sex, embryo fragmentation, treatment protocols, diferent culture media, and embryo morphokinetics will be examined based on some new researches of TLI facilities. Furthermore, various algorithms and predictive models designed in ART cycles with TLI will be discussed.

Background: Embryo quality may affect birth weight among neonates born through assisted reproductive technology. There are very limited studies assessing the adverse effect of transferring a poor-quality embryo with a good-quality one on neonatal outcomes. Objective: The aim of this study was to evaluate the effect of double embryo transfer (DET) with one good-quality embryo (GQE) plus a poor-quality one on the birth weight of newborns conceived by in vitro fertilization in both fresh and frozen-thawed embryo transfer cycles. Materials and Methods: This study was conducted at Yazd Reproductive Sciences Institute, Yazd, Iran. A total of 626 women were classified into three groups according to the embryo quality: single embryo transfer with a GQE (group A); DET using two GQEs (group B); and DET using one good-quality and one poor-quality embryo (group C). The primary outcome was singleton birth weight which was compared between the three groups among fresh and frozen-embryo transfer cycles. A comparative analysis was also performed regarding the effect of vitrification procedures on neonatal birth weight within each of the three embryo quality-based groups. Results: The mean birth weight and the rate of preterm birth were similar between the three groups (p = 0.45 and 0.32, respectively). There were also no significant differences found in the vitrification comparative analysis between and within the groups with regard to birth weight. Conclusion: Our results showed that a poor-quality embryo did not have a significant influence on a good-quality one regarding neonatal birth weight when transferred together. Key words: Embryo quality, Birth weight, Frozen-embryo transfer, Fresh embryo transfer, Single embryo transfer, Double embryo transfer.

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