Culture systems for the human embryo
David K. Gardner, Ariel Weissman, Colin M. Howles, Zeev Shoham in Textbook of Assisted Reproductive Techniques, 2017
Embryo culture is frequently mistaken for a relatively simple procedure. In reality, it is a complex task, requiring proactive quality control and quality assurance programs to ensure the optimum performance of the laboratory and equipment, together with a high level of training for embryologists. Furthermore, a sufficient number of suitable incubation chambers are required to maintain a stable environment for development in vitro. Hence, embryo culture is far more involved than simply using the appropriate culture media formulations. Consequently, in order to optimize embryo development in vitro and maintain viability to ensure the delivery of a healthy baby, it is essential to consider embryo culture as a system in its entirety. The embryo culture system consists of the media, macromolecules, gas phase, type of medium overlay, the culture vessel, the incubation chamber, ambient air quality, and even the embryologists themselves. The concept of an embryo culture system successfully highlights the interactions that exist not only between the embryo and its physical surroundings, but also between all parameters within the laboratory (Figure 16.1). Only by taking such a holistic approach can one optimize embryo development in vitro and maintain success rates.
Use of Blastocyst Culture
Botros Rizk, Yakoub Khalaf in Controversies in Assisted Reproduction, 2020
A Cochrane review (24) included 32 studies: 17 studies of randomized women (total 3666), 3 randomized cycles (total 1018), and 12 randomized oocytes (over 15,230). It was not possible to pool any of the data because each study compared different culture media. Only seven studies reported live birth or ongoing pregnancy. Four of these studies found no evidence of a difference between the media compared, for either day 3 or day 5 embryo transfer. Most studies (22/32) failed to report their source of funding, and none described their methodology in adequate detail. The overall quality of the evidence was rated as very low for nearly all comparisons. The authors’ conclusions were that an optimal embryo culture medium is important for embryonic development and, subsequently, the success of IVF or ICSI treatment. There has been much controversy about the most appropriate embryo culture medium. Numerous studies have been performed, but no two studies compared the same culture media, and none of them found any evidence of a difference between the culture media used. We conclude that there is insufficient evidence to support or refute the use of any specific culture medium. Properly designed and executed randomized trials are necessary.
Epigenetic and Assisted Reproduction Experimental Studies
Cristina Camprubí, Joan Blanco in Epigenetics and Assisted Reproduction, 2018
Regarding embryo culture, Kleijkers et al. (65) reported how the age of the culture medium inversely affects the birthweight of singletons born after IVF (66); and Ceelen et al. (50) showed that a prolonged embryo culture in vitro is associated with high odds of preterm birth (50). Dumoulin et al. (67) and Zandstra et al. (68) revealed that the type of culture media can affect human neonatal birthweight (68) (Figure 11.3). Other studies have reported variations in gene expression between the different media studied (65). The type of culture media is also related with a big placenta size (46), so it is likely that the culture medium affects embryonic development affecting the birthweight (65) and could alter growth patterns until two years of age (68). Ghosh et al. (2017) analyzed placental DNA methylation levels at repeated sequences to study the effect of ART and in vitro culture. They found that global methylation levels differed between placentas from natural conceptions compared to placentas conceived by IVF, and between placentas conceived by IVF in different culture conditions (different O2 percentage) (42).
Embryo culture using a time-lapse monitoring system improves live birth rates compared with a conventional culture system: a prospective cohort study
Published in Human Fertility, 2018
Lihong Wu, Wei Han, Jiang Wang, Xiaodong Zhang, Weiwei Liu, Shun Xiong, Shubiao Han, Junxia Liu, Yang Gao, Guoning Huang
Embryo culture is a critical component of in vitro fertilization (IVF). Current in vitro embryo culture technology cannot fully recapitulate the in vivo environment for proper embryonic development. Sub-optimal in vitro culture environment may impair the development potential of such embryos. Since the first ‘test-tube’ baby was born in 1978, embryologists have been dedicated to improving the in vitro environment for embryo culture. For example, the use of sequential culture medium replaced the use of a single-culture medium (Biggers, McGinnis, & Lawitts, 2005; Biggers & Summers, 2008; Gardner & Lane, 1998) and the well-of-the-well (WOW) group-culture technique replaced the microdrop technique (Dal Canto et al., 2012; Sugimura et al., 2010; Vajta, et al., 2008, 2000). In addition, culture systems have changed from static to dynamic systems, such as mechanical vibration during in vitro maturation and/or in vitro culture, tilting embryo culture, microfluidic in vitro cultivation, etc. (Kim, Bae, Wee, Han, & Park, 2009; Matsuura et al., 2010; Mizobe, Yoshida, & Miyoshi, 2010; Pennathur, 2008). These techniques demonstrate improved embryonic developmental potential to some extent, although some techniques (i.e. dynamic culture systems) have not been widely used in IVF laboratories.
Should all embryos be cultured to blastocyst for advanced maternal age women with low ovarian reserve: a single center retrospective study
Published in Gynecological Endocrinology, 2018
Panyu Chen, Tingting Li, Lei Jia, Cong Fang, Xiaoyan Liang
Social trends around the world have led women to delay child-bearing into their 30 s and, in some cases, their 40 s. In China, the average age of women giving birth has increased from 26 to 28 over the last 20 years. With China’s fully implementing ‘the second child’ policy in 2016, more women begin to prepare for their second child, including lots of women older than 37. Female aging is accompanied by lower fecundity, decreasing ovarian function, worse quality of eggs and increasing oocyte aneuploidy rate, which lead to increasing miscarriage rates, reduced pregnancy rate and live birth rate. Hence, many advanced maternal age (AMA) patients turn to assisted reproductive technique (ART). However, ART does not fully compensate for the decline in natural fertility. We are facing various problem such as repeated bad quality embryos, low pregnancy rate/high miscarriage rate in AMA patients. Extending embryo culture to the blastocyst stage can increase the odds of transferring viable, genetically normal embryos and can be an important tool for better embryo selection in advanced maternal age. However, blastocyst culture requires more suitable environment in embryo lab and strict technique of embryologist. Plus, it has a higher risk of cycle cancelation.
Comparison between embryos transferred with self-spent and fresh medium on reproductive outcomes: a prospective randomized trial
Published in Systems Biology in Reproductive Medicine, 2020
Bin Wu, Bo Yan, Rui Hu, Shan Tian, Yali Ni, Yu Liang, Yunshan Wang, Yingchun Zhang
After obtaining high-quality embryos through embryo culture, the key to ensuring a successful pregnancy is to transfer the embryo into the uterine cavity in a suitable manner at the right time. Variables during embryo transfer (ET) have been confirmed to have an impact on subsequent pregnancy, such as expulsion of embryos, touching fundus, blood, or mucus on the catheter tip and bacterial contamination (Schoolcraft 2016). In addition, the choice of volume and type of transfer media during transplantation is also worthy of attention. Although commercialized transfer media supplemented with hyaluronan (HA) are now readily available, most reproductive medicine centers still use conventional fresh cleavage or blastocyst medium as a transfer media mainly due to the fact that controversy has always existed whether HA-enriched culture fluids can significantly improve clinical pregnancy (Urman et al. 2008; Nakagawa et al. 2012; Fancsovits et al. 2015). Therefore, research on transfer media still needs to be further performed, especially in terms of the effects of media components on embryo potential and endometrial receptivity.
Related Knowledge Centers
- Embryonic Development
- Embryo Transfer
- In Vitro Fertilisation
- Preterm Birth
- Blastocyst
- Preimplantation Genetic Diagnosis
- Pregnancy Rate
- Twin
- Cleavage
- Odds Ratio