How the baby is “27 years old” at birth
An embryo that had been frozen for 27 years was "adopted" and developed into a normal newborn.
Her birth set a new record for human embryo preservation, meaning that as long as the embryo is properly preserved in liquid nitrogen, it can theoretically remain active indefinitely.
As the saying goes, "Pregnant in October, give birth at once."
However, according to a report by the National Broadcasting Corporation on December 2, an embryo was only "adopted" by a woman from the National Embryo Donation Center in Tennessee in February this year after being frozen for 27 years.
Eight months later, the woman gave birth to a newborn named Molly.
The birth of Molly's health also created a new record of human life.
In response, the National Embryo Donation Center of the United States stated in a statement that “the technology used many years ago may have no time limit in terms of embryo preservation capacity”, which means that as long as the embryos are properly stored in liquid nitrogen, they can theoretically remain active indefinitely. .
Technology: embryos from freezing to recovery conditions are mature
"At present, the frozen embryo technology is relatively mature, and there is not much technical difficulty." According to Shuai Ling, a researcher at the State Key Laboratory of Medicinal Chemistry and Biology of Nankai University, frozen embryos are a derivative technology of IVF technology. Generally speaking, it will be 1-2 After the embryos are transferred back to the human uterus, the excess embryos will be frozen.
"Frozen embryos are currently stored in liquid nitrogen. The temperature of liquid nitrogen is -196℃. In liquid nitrogen, the activity of cell enzymes is almost completely inhibited, which means that the cell process is in a stagnant state." Shuai said, Embryos will not age when stored in liquid nitrogen. The storage time has no significant effect on their developmental potential and the health of the child. At present, the survival rate of thawing and resuscitation can reach almost 100%.
70% of human cells are water. When water turns from liquid to solid, it will crystallize, and ice crystals will stab the cells.
How can we ensure that the embryo will not be frozen?
"The formation of ice crystals is the main reason for the damage of frozen embryos. Therefore, the current embryo freezing technology is to reduce the formation of ice crystals during the freezing process." According to Shuai, there are two main types of embryo freezing technology, programmed slow freezing and vitrification.
Programmed slow freezing is to use computer control to slowly lower the temperature of the embryo. In order to prevent the water from producing ice crystals, cryoprotectants are added to make it penetrate and fill the embryo, replacing most of the water in the embryo; vitrification is Let the embryos undergo a brief treatment in a high-concentration cryoprotectant and then put them directly into liquid nitrogen.
Du Yongrui, director of the embryo laboratory of the Reproductive Medicine Department of Tianjin Medical University Second Hospital, said that after 2008, the reproductive medicine centers nationwide basically adopted the method of vitrification.
At present, most of the freezing kits used by the Center for Reproductive Medicine are imported commercial kits, but there are already domestically-made freezing kits that have obtained approval numbers and will be on the market soon.
In the process of cryopreservation of embryos, it is also necessary to avoid contamination by bacteria and viruses.
"Carriers for embryo cryopreservation are divided into open and closed forms. During freezing, the open carrier will cool down faster. However, since liquid nitrogen cannot be effectively disinfected, theoretically there are bacteria and viruses. The risk of contamination, but there is no relevant report.” Du Yongrui said that in general, the Reproductive Medicine Center will store the embryos of hepatitis B virus carriers and syphilis-positive patients separately to avoid the risk of pathogenic microorganism contamination.
For embryos that have undergone a long "hibernation" to finally "wake up", a process of recovery is needed.
The resuscitation process is to use a thawing reagent to adjust the osmotic pressure to allow the water to return to the embryo. Generally speaking, the thawing process can be completed in about 10 minutes.
Reality: The "fetuses" of my country's reproductive medicine center are full
Frozen embryo technology has been developed with the development of IVF technology, and the technology is currently widely used in assisted reproduction.
In my country, the technology of freezing embryos has developed more maturely, and more and more families have benefited from this.
In 2017, Zhongshan Hospital of Guangdong Province successfully gave birth to an "ice baby" frozen for 18 years, which is also the "second child ice baby" with the longest freezing time in China.
And another sister embryo, born at the same time as her, is now her 18-year-old adult sister.
"There are currently nearly 500 reproductive medicine centers in China, and each center will have embryo cryopreservation rooms." According to Du Yongrui, generally freezer rooms will be equipped with dozens to dozens of liquid nitrogen storage tanks, and the liquid nitrogen tanks are equipped with automatic The alarm system monitors the height of the liquid nitrogen surface and the temperature in the tank every day. When it is below a certain value, it will remind you to replenish the liquid nitrogen in time.
In addition, there will be anti-theft, anti-mismatch and other related equipment support.
When most reproductive medicine centers perform IVF treatments, they will sign an Informed Consent for the Freezing, Thawing and Transfer of Embryos and Blastocysts with the patient’s couple, regarding whether to preserve the remaining embryos and whether to discard the embryos after the preservation period. Undergo verification.
There will be a certain cost for preservation, and a one to two year shelf life agreement can be signed.
The preservation period approaches, the center will notify the depositary and ask whether to renew the deposit.
"Many couples who still want to have a second child may choose to renew the fee for preservation, but there will still be couples who forget their frozen embryos." Du Yongrui said helplessly. Although the agreement has been signed, most reproductive medicine centers will still pay after the expiration of the preservation period. Embryos continue to be preserved, so the freezing rooms of many hospitals are full of "fetuses", and liquid nitrogen storage tanks continue to increase.
Small centers increase a few each year, and large centers increase a dozen or even twenty a year. Generally, a 35-liter storage tank can store thousands of embryos.
"At present, many centers still store embryos frozen around 2000, and the number of embryos with a freezing period of more than 10 years is also quite large." Du Yongrui said, in fact, frozen embryos more than 20 years old, because the mother's age is already very old, almost never Then choose resuscitation and implantation. Only in very few cases, after the accidental death of one child, choose to resuscitate frozen embryos, risking the risk of advanced pregnancy.
The Reproductive Medicine Branch of the Chinese Medical Association "Consensus of Chinese Experts on the Preservation Period of Frozen Embryos" suggested that if the freezing time exceeds 10 years, and the woman is over 52 years old, it is of little significance to retain frozen embryos, and a large amount of medical resources are wasted.
The future: legislation related to frozen embryos needs to be improved
The birth of this 27-year-old "older" baby once again aroused people's discussion on the ethics of frozen embryos.
Many people worry that if a couple’s frozen embryos are thawed after more than 20 years and are implanted in a daughter suffering from infertility, will the daughter give birth to the couple’s grandson (daughter) or children?
Regarding this concern, Du Yongrui said that the current regulations for the management of frozen embryos in my country-the "Human Assisted Reproductive Technology Regulations" stipulate that medical technicians are prohibited from implementing surrogacy technology and donating embryos.
In judicial practice, if frozen embryos are illegally bought and sold, the civil act is invalid due to the harm to the public interest of the society. Serious circumstances may constitute a crime.
In other words, the embryo can only be resuscitated if the parents of the frozen embryo sign and agree, and the embryo can only be implanted in the mother's womb.
However, all countries in the world are facing the problem of imperfect laws in the supervision process of frozen embryos.
In 2014, a couple obtained 4 embryos through IVF surgery. Before the transplant could be performed, the couple died in a car accident.
Both parents hoped to obtain the right to dispose of embryos, but the court held that the fertilized eggs produced during in vitro fertilization-embryo transfer surgery have the potential to develop into life, are special objects with future life characteristics, and cannot be inherited objects. The judgment dismissed the plaintiff's claims.
Cases concerning the right to dispose of frozen embryos are not uncommon in recent years.
Whether the frozen embryo is a human or a thing, there are different opinions in the theoretical circles, and there are many differences in foreign legal precedents.
When both husband and wife have passed away, whether the frozen embryos kept in medical institutions belong to the inheritance and whether they can be inherited is also one of the focuses of disputes.
With the development of assisted reproductive technology and the increasing demand of the people, there are more and more disputes arising from assisted reproductive technology.
The imperfect legislation will cause the court’s adjudication dilemma to become more prominent.
The biological properties of embryos may involve many legal issues such as the identification of children's identity, inheritance of property, compensation for infringement damages, etc. Therefore, legislation should maintain a certain cutting edge. With the development of relevant medical technology in China, departmental regulations should be revised and improved as soon as possible.