Introduction
Most commonly, after an embryo is created through in-vitro fertilization, the embryo grows in a culture media for several days before being frozen (cryopreservation). The exception would be in the rare practice of a fresh embryo transfer cycle in which the embryo will be transferred back to the uterus after several days of growth to allow for a chance at implantation, thus avoiding cryopreservation. In the more commonly performed frozen embryo transfer, embryos are frozen several days post-fertilization to be thawed and transferred at a later time. The question arises as to whether Christians may engage in the cryopreservation of their own children in their embryonic stage of development.
Why Cryopreservation is Done
Regarding a couple’s initial transfer, embryos may be frozen to (1) allow time for preparing a woman’s uterine lining via hormone medications to optimize implantation success rates and/or to (2) allow time for the pre-implantation genetic testing (PGT) results to come back to inform decisions as to which embryos to transfer. As with most IVF cases, more embryos are created than are transferred in the first cycle and thus embryos are commonly frozen to allow for subsequent transfer cycles in the future.
Concerns and Considerations Relating to Cryopreservation
- Harm to the child
Not every child will survive the thawing process, and as every child will need to be thawed prior to being transferred, there are concerns whether freezing these children and inevitably subjecting them to the thawing process constitutes significant harm and child endangerment.
Unfortunately, the reported data regarding the success rate of thawing is quite variable and depends on multiple factors (ie, stage of development of the child at the time of freezing, the method of freezing and thawing, the grade of the embryo, etc). In a 2011 article published in the Journal of Human Reproductive Science, the thaw survival rate for zygote, D3, and blastocyst were 69%, 85%, and 88% respectively.1 Most IVF clinics self-report a survival rate upwards of 90%.2 The National Embryo Donation Center (NEDC) reports a thaw survival rate of 75%. In our personal adoption journey, our first transfer resulted in two children out of five not surviving the thawing process, thus a survival rate of 60%.3
It seems reasonable to cautiously conclude a thaw survival rate of 75-95%. 95% being the upper range as most commonly self-reported by IVF clinics. It should be noted that there are a few clinics reporting higher than 95% survival rates though it is likely those data points are outliers. It is important to consider that self-reported data from IVF clinics is likely overestimating the true survival rate as it is common practice to destroy poorly-graded embryos and thus not include them in the thaw survival data. The lower range of 75% comes from the reported data from the National Embryo Donation Center (NEDC). As this organization facilitates embryo adoption and transfers of all embryos regardless of quality, it is likely that their data underestimates the true survival rate as NEDC will thaw all adopted embryos that are being transferred regardless of the grading of the embryo.
That a child has a 75-95% chance of surviving a medical procedure should be a reason for cautioning and reconsidering the widespread practice of cryopreservation. - Biblical parenting
The biblical command for parents is to raise one’s children in the discipline and instruction of the Lord (Eph. 6:4). The command “to bring [children] up” connotes active personal involvement. One would need to consider whether they are fulfilling their biblical mandate as parents to these children if left frozen often times for long periods of times.
It is worth considering whether the intentional suspending of a child in time per se through cryopreservation is consistent with God’s mandate to parents. - Uncertainty of the future
In 2018, there were multiple embryo/egg storage tank failures around the United States resulting in the loss of thousands of embryos and eggs.3 It is not clear how often tank failures occur as there is little regulatory oversight4 however it is another consideration to examine.
In addition, while many couples create more children than they intend to ever transfer, other couples create the number of children they would be willing to transfer (through one or multiple cycles) only to decide later on that they do not want to raise more children.
Alternative to Cryopreservation
Cryopreserving embryos is not an inevitable, indispensable part of the IVF process. While nearly all IVF cases today result in the freezing of embryos, it is nonetheless an intentional choice or a consequence of choices made by a couple. An alternative is to pursue a fresh embryo transfer which requires the creating of only the specific number of children a couple would like to transfer several days post-fertilization.
In this 2018 clinical trial published in the New England Journal of Medicine5, there was no statistically significant difference in live birth-rate between fresh embryo transfer and frozen embryo transfer in ovulatory women with infertility. This would suggest that there is no benefit to the embryo in pursuing a frozen transfer that could outweigh the risk of the embryo not surviving the thawing process.a
Concluding Thoughts
As the world continues to live in hostility and rebellion to God, it should not surprise the Christian that the practices of the world often oppose the will and design of God. In dehumanizing the unborn, the world does not wrestle with whether freezing children constitutes child endangerment and violates the expressed will of God. It would seem prudent for the Christian to address and examine the above concerns prior to engaging in the normative IVF practice of cryopreservation.
Notes
a
There are a few studies showing anovulatory women with polycystic ovary syndrome have a higher chance of successful implantation and pregnancy with a frozen embryo transfer rather than a fresh embryo transfer. In select women, it may be reasonable to consider whether an embryo has a higher chance of survival going through the freezing and thawing process and undergoing a frozen transfer rather than a fresh transfer.
I also want to briefly mention that the risk of ovarian hyperstimulation syndrome in the women should also be considered.
References
1 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3136065/
2 https://blog.scrcivf.com/frozen-embryo-success-rates
https://www.inviafertility.com/blog/embryology/kellyschorsch/all-about-thawing-frozen-embryo/
https://reuniterx.com/fertility-articles/is-freezing-embryos-safe-how-many-survive-the-thaw/
3 https://www.nytimes.com/2018/03/28/us/frozen-embryos-eggs.html
4 https://www.nbcnews.com/news/all/heartbreak-anxiety-lawsuits-egg-freezing-disaster-year-later-n978891
5 https://www.nejm.org/doi/pdf/10.1056/NEJMoa1705334
Foreknown and Created 