Embryo cryopreservation

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Cryopreservation of embryos is the process of preserving an embryo at sub-zero temperatures, generally at an embryogenesis stage corresponding to pre-implantation, that is, from fertilisation to the blastocyst stage.

Contents

Indications

Embryo cryopreservation is useful for leftover embryos after a cycle of in vitro fertilisation, as patients who fail to conceive may become pregnant using such embryos without having to go through a full IVF cycle. Or, if pregnancy occurred, they could return later for another pregnancy. Spare oocytes or embryos resulting from fertility treatments may be used for oocyte donation or embryo donation to another woman or couple, and embryos may be created, frozen and stored specifically for transfer and donation by using donor eggs and sperm.

Method

Embryo cryopreservation is generally performed as a component of in vitro fertilization (which generally also includes ovarian hyperstimulation, egg retrieval and embryo transfer). The ovarian hyperstimulation is preferably done by using a GnRH agonist rather than human chorionic gonadotrophin (hCG) for final oocyte maturation, since it decreases the risk of ovarian hyperstimulation syndrome with no evidence of a difference in live birth rate (in contrast to fresh cycles where usage of GnRH agonist has a lower live birth rate). [1]

The main techniques used for embryo cryopreservation are vitrification versus slow programmable freezing (SPF). Studies indicate that vitrification is superior or equal to SPF in terms of survival and implantation rates. [2] Vitrification appears to result in decreased risk of DNA damage than slow freezing. [3] Vitrification prevent ice crystals in gametes. It is so fast (-23000 °C/min) that these crystals do not appear. [4] Still, the amount of cryoprotectant used in the vitrification is crucial: too much is toxic for the embryo; but too little could cause the appearance of crystallised water, regardless of the speed at which the process is carried out. There are two types of vitrification system. In the open vitrification system, the sample has direct contact with liquid nitrogen, which allows ultra-fast freezing. In the closed vitrification system, samples are placed in a sealed device before being immersed in liquid nitrogen. In this way, the sample is protected from any direct contact with nitrogen. It is used to cryopreserve biological risk samples.

Direct Frozen Embryo Transfer: Embryos can be frozen by SPF in ethylene glycol freeze media and transfer directly to recipients immediately after water thawing without laboratory thawing process. The world's first crossbred bovine embryo transfer calf under tropical conditions was produced by such technique on 23 June 1996 by Dr. Binoy S Vettical of Kerala Livestock Development Board, Mattupatti [5] [6]

Prevalence

World usage data is hard to come by but it was reported in a study of 23 countries that almost 42,000 frozen human embryo transfers were performed during 2001 in Europe. [7]

Pregnancy outcome and determinants

In current state of the art, early embryos having undergone cryopreservation implant at the same rate as equivalent fresh counterparts. [2] The outcome from using cryopreserved embryos has uniformly been positive with no increase in birth defects or development abnormalities, [3] [8] also between fresh versus frozen eggs used for intracytoplasmic sperm injection (ICSI). [9] In fact, pregnancy rates are increased following frozen embryo transfer, and perinatal outcomes are less affected, compared to embryo transfer in the same cycle as ovarian hyperstimulation was performed. [10] The endometrium is believed to not be optimally prepared for implantation following ovarian hyperstimulation, and therefore frozen embryo transfer avails for a separate cycle to focus on optimizing the chances of successful implantation. [10] Children born from vitrified blastocysts have significantly higher birthweight than those born from non-frozen blastocysts. [11] For early cleavage embryos, frozen ones appear to have at least as good obstetric outcome, measured as preterm birth and low birthweight for children born after cryopreservation as compared with children born after fresh cycles. [9]

Oocyte age, survival proportion, and number of transferred embryos are predictors of pregnancy outcome. [12]

Pregnancies have been reported from embryos stored for 27 years. [13] A study of more than 11,000 cryopreserved human embryos showed no significant effect of storage time on post-thaw survival for IVF or oocyte donation cycles, or for embryos frozen at the pronuclear or cleavage stages. [12] In addition, the duration of storage had no significant effect on clinical pregnancy, miscarriage, implantation, or live birth rate, whether from IVF or oocyte donation cycles. [12]

A study in France between 1999 and 2011 came to the result that embryo freezing before administration of gonadotoxic chemotherapy agents to females caused a delay of treatment in 34% of cases, and a live birth in 27% of surviving cases who wanted to become pregnant, with the follow-up time varying between 1 and 13 years. [14]

Legislation

From 1 October 2009, human embryos are allowed to be stored for 10 years in the UK, according to the Human Fertilisation and Embryology Act 2008. [15]

History

The cryopreservation of embryos was first successfully attempted in 1984 in the case of Zoe Leyland, the first baby to be born from a frozen embryo. [16] In Zoe's case, the embryo had been frozen for two months, but since the inception of the practice of cryopreservation after successful IVF, embryos have successfully survived in cryopreservation extensively longer periods of time, spanning even decades. [16] The long-term implications of freezing embryos are demonstrated in the case of Molly Everette Gibson, the child born from the viable pregnancy of her mother who used an embryo, which had been stored in a cryogenic freezer for twenty-seven years. [17] The first twins derived from frozen embryos were born in February 1985. [18] Since then and up to 2008 it is estimated that between 350,000 and half a million IVF babies have been born from embryos frozen at a controlled rate and then stored in liquid nitrogen; additionally a few hundred births have been born from vitrified oocytes but firm figures are hard to come by.

It may be noted that Subash Mukhopadyay from Kolkata, India reported the successful cryopreservation of an eight cell embryo, storing it for 53 days, thawing and replacing it into the mother's womb, resulting in a successful and live birth as early as 1978- a full five years before Trounson and Mohr had done so. A small publication of Mukherjee in 1978 [19] clearly shows that Mukherjee was on the right line of thinking much before anyone else had demonstrated the successful outcome of a pregnancy following the transfer of a 8-cell frozen-thawed embryo into human subjects transferring 8-cell cryopreserved embryos. [20] [21]

Implications

The practice of cryopreservation of embryos has increased in recent years. [22] While the original purpose of freezing embryos was to help heterosexual couples who struggled with infertility, the practice has become an increasingly common avenue to start a family for homosexual couples, single women, as well as surrogates. [22] Prior to successful attempts to effectively freeze embryos for later use, individuals were limited in their assisted reproductive technology options to in vitro fertilization (IVF), whereby sperm and egg were combined in a lab to create the embryos, all of which then had to be immediately implanted into the mother. [22] Cryopreservation enables the embryos to be safely stored for extensive periods of time. [16] Individuals are then able choose the proper time to use the embryos as well as elect to use only one embryo at a time while saving the others for later use. [16] Doing so reduces the possibility of conceiving twins or triplets, thus allowing parents to exercise greater control over their vision for their families. [16] Additionally, embryos may be tested and manipulated to eliminate genetic diseases. [23]

While the cryopreservation of embryos has been characterized by great scientific developments over the years, [23] the treatment of allocation of embryos in the event of a divorce or separation of the parties is a broadening and still less developed area of the law which continues to present challenges for the courts today. Politicians, state legislatures, and courts grapple with a multitude of legal issues surrounding families created using fertility treatments in view of divergent moral, political, and legal discourse throughout the United States. [23] For example, in Illinois, the courts employ at least two clear approaches to determining how embryos are allocated in the event of a divorce or separation of the parties. [24] Specifically, the courts seek to enforce any contractual language surrounding the allocation of the embryos, and they also employ a balancing test of the parties’ interests alongside the contractual approach or simply as an alternative approach if no contract exists. [24] State courts are often left to decide these issues as statutory resources are not well-developed across the states. For example, in Illinois, the Illinois Parentage Act of 2015 has contemplated situations in which parties, represented by independent legal counsel, enter into contractual agreements regarding the allocation of embryos, but no uniform statutory answer exists for situations in which parties failed to enter into such written agreements regarding allocation. [25]

Related Research Articles

<span class="mw-page-title-main">In vitro fertilisation</span> Assisted reproductive technology procedure

In vitro fertilisation (IVF) is a process of fertilisation in which an egg is combined with sperm in vitro. The process involves monitoring and stimulating a woman's ovulatory process, then removing an ovum or ova from her ovaries and enabling a man's sperm to fertilise them in a culture medium in a laboratory. After a fertilised egg (zygote) undergoes embryo culture for 2–6 days, it is transferred by catheter into the uterus, with the intention of establishing a successful pregnancy.

<span class="mw-page-title-main">Intracytoplasmic sperm injection</span> In vitro fertilization procedure

Intracytoplasmic sperm injection is an in vitro fertilization (IVF) procedure in which a single sperm cell is injected directly into the cytoplasm of an egg. This technique is used in order to prepare the gametes for the obtention of embryos that may be transferred to a maternal uterus. With this method, the acrosome reaction is skipped.

Cryobiology is the branch of biology that studies the effects of low temperatures on living things within Earth's cryosphere or in science. The word cryobiology is derived from the Greek words κρῧος [kryos], "cold", βίος [bios], "life", and λόγος [logos], "word". In practice, cryobiology is the study of biological material or systems at temperatures below normal. Materials or systems studied may include proteins, cells, tissues, organs, or whole organisms. Temperatures may range from moderately hypothermic conditions to cryogenic temperatures.

<span class="mw-page-title-main">Embryo transfer</span> Method of assisted reproduction

Embryo transfer refers to a step in the process of assisted reproduction in which embryos are placed into the uterus of a female with the intent to establish a pregnancy. This technique - which is often used in connection with in vitro fertilization (IVF) - may be used in humans or in other animals, in which situations and goals may vary.

Ovarian hyperstimulation syndrome (OHSS) is a medical condition that can occur in some women who take fertility medication to stimulate egg growth, and in other women in sporadic cases. Most cases are mild, but rarely the condition is severe and can lead to serious illness or even death.

Embryo donation is one disposition option for users of in vitro fertilisation with remaining fresh or frozen embryos. It is defined as the giving—generally without compensation—of embryos remaining after in vitro fertilization procedures to recipients for procreative implantation or research. Most IVF users with supernumerary embryos make embryo donation decisions after completing their families or discontinuing use of in vitro fertilization. Recipients of embryos donated for procreative implantation typically plan to transfer fresh or frozen embryos into a prepared uterus in order to facilitate pregnancy and childbirth. Recipients of embryos donated for research typically use them for clinical training, quality improvement research, or human embryonic stem cell research.

<span class="mw-page-title-main">Oocyte cryopreservation</span> Procedure to preserve a womans eggs (oocytes)

Oocyte cryopreservation is a procedure to preserve a woman's eggs (oocytes). This technique is often used to delay pregnancy. When pregnancy is desired, the eggs can be thawed, fertilized, and transferred to the uterus as embryos. Several studies have shown that most infertility problems are due to germ cell deterioration related to aging. The procedure's success rate varies depending on the woman's age, health, and genetic factors. The first human birth of oocyte cryopreservation was reported in 1986.

Controlled ovarian hyperstimulation is a technique used in assisted reproduction involving the use of fertility medications to induce ovulation by multiple ovarian follicles. These multiple follicles can be taken out by oocyte retrieval for use in in vitro fertilisation (IVF), or be given time to ovulate, resulting in superovulation which is the ovulation of a larger-than-normal number of eggs, generally in the sense of at least two. When ovulated follicles are fertilised in vivo, whether by natural or artificial insemination, there is a very high risk of a multiple pregnancy.

<span class="mw-page-title-main">In vitro maturation</span> Artificial maturation of harvested immature egg cells

In vitro maturation (IVM) is the technique of letting the contents of ovarian follicles and the oocytes inside mature in vitro. It can be offered to women with infertility problems, combined with In Vitro Fertilization (IVF), offering women pregnancy without ovarian stimulation.

Transvaginal oocyte retrieval (TVOR), also referred to as oocyte retrieval (OCR), is a technique used in in vitro fertilization (IVF) in order to remove oocytes from an ovary, enabling fertilization outside the body. Transvaginal oocyte retrieval is more properly referred to as transvaginal ovum retrieval when the oocytes have matured into ova, as is normally the case in IVF. It can be also performed for egg donation, oocyte cryopreservation and other assisted reproduction technology such as ICSI.

Fertility preservation is the effort to help cancer patients retain their fertility, or ability to procreate. Research into how cancer, ageing and other health conditions effect reproductive health and preservation options are growing. Specifically sparked in part by the increase in the survival rate of cancer patients.

<span class="mw-page-title-main">Cryopreservation</span> Process to preserve biological matter

Cryopreservation or cryoconservation is a process where biological material - cells, tissues, or organs - are frozen to preserve the material for an extended period of time. At low temperatures any cell metabolism which might cause damage to the biological material in question is effectively stopped. Cryopreservation is an effective way to transport biological samples over long distances, store samples for prolonged periods of time, and create a bank of samples for users. Molecules, referred to as cryoprotective agents (CPAs), are added to reduce the osmotic shock and physical stresses cells undergo in the freezing process. Some cryoprotective agents used in research are inspired by plants and animals in nature that have unique cold tolerance to survive harsh winters, including: trees, wood frogs, and tardigrades. The first human corpse to be frozen with the hope of future resurrection was James Bedford's, a few hours after his cancer-caused death in 1967.[15] Bedford's is the only cryonics corpse frozen before 1974 still frozen today.

Ovarian tissue cryopreservation is cryopreservation of tissue of the ovary of a female.

Semen cryopreservation is a procedure to preserve sperm cells. Semen can be used successfully indefinitely after cryopreservation. It can be used for sperm donation where the recipient wants the treatment in a different time or place, or as a means of preserving fertility for men undergoing vasectomy or treatments that may compromise their fertility, such as chemotherapy, radiation therapy or surgery. It is also often used by trans women prior to medically transitioning in ways that affect fertility, such as feminizing hormone therapy and orchiectomies.

Natural Cycle In Vitro Fertilization (IVF) is an assisted reproductive technique designed to closely mimic a woman's natural menstrual cycle. In traditional IVF, a woman's ovaries are stimulated with fertility medications to produce multiple eggs, which are then retrieved and fertilized outside the body. A natural cycle IVF, on the other hand, works with the woman's natural hormonal fluctuations and ovulation cycle.

Jacques Cohen is a Dutch embryologist based in New York. He is currently a Director at Reprogenetics LLC, Laboratory Director at ART Institute of Washington at Walter Reed National Military Medical Center, and Scientific Director of R & D at IVF-online.

Luteal support is the administration of medication, generally progesterone, progestins, hCG or GnRH agonists, to increase the success rate of implantation and early embryogenesis, thereby complementing and/or supporting the function of the corpus luteum. It can be combined with for example in vitro fertilization and ovulation induction.

The history of in vitro fertilisation (IVF) goes back more than half a century. In 1959 the first birth in a nonhuman mammal resulting from IVF occurred, and in 1978 the world's first baby conceived by IVF was born. As medicine advanced, IVF was transformed from natural research to a stimulated clinical treatment. There have been many refinements in the IVF process, and today millions of births have occurred with the help of IVF all over the world.

Induction of final maturation of oocytes is a procedure that is usually performed as part of controlled ovarian hyperstimulation to render the oocytes fully developed and thereby resulting in optimal pregnancy chances. It is basically a replacement for the luteinizing hormone (LH) surge whose effects include final maturation in natural menstrual cycles.

<span class="mw-page-title-main">Use of assisted reproductive technology by LGBT people</span>

Lesbian, gay, bisexual, and transgender people people wishing to have children may use assisted reproductive technology. In recent decades, developmental biologists have been researching and developing techniques to facilitate same-sex reproduction.

References

  1. ↑ Youssef, Mohamed AFM; Van der Veen, Fulco; Al-Inany, Hesham G; Mochtar, Monique H; Griesinger, Georg; Nagi Mohesen, Mohamed; Aboulfoutouh, Ismail; van Wely, Madelon; Youssef, Mohamed AFM (2014). "Cochrane Database of Systematic Reviews: Gonadotropin-releasing hormone agonist versus HCG for oocyte triggering in antagonist-assisted reproductive technology". Reviews (10): CD008046. doi:10.1002/14651858.CD008046.pub4. PMC   10767297 . PMID   25358904.
  2. 1 2 Edgar, D. H.; Gook, D. A. (2012). "A critical appraisal of cryopreservation (slow cooling versus vitrification) of human oocytes and embryos". Human Reproduction Update. 18 (5): 536–554. doi:10.1093/humupd/dms016. PMID   22537859.
  3. 1 2 Kopeika, J.; Thornhill, A.; Khalaf, Y. (2014). "The effect of cryopreservation on the genome of gametes and embryos: principles of cryobiology and critical appraisal of the evidence". Human Reproduction Update. 21 (2): 209–227. doi: 10.1093/humupd/dmu063 . ISSN   1355-4786. PMID   25519143.
  4. ↑ C Schiewe, Mitchel (6 September 2017). "Vitrification: the pioneering past to current trends and perspectives of cryopreserving human embryos, gametes and reproductive tissue" (PDF). Journal of Biorepository Science for Applied Medicine. 2017 (5): 57–68. doi: 10.2147/BSAM.S139376 . Retrieved 9 January 2022.
  5. ↑ Cryopreservation of Embryos in Ethylene Glycol Freeze Media and Direct Transfer in Crossbred Cattle in the Tropics,9th International Congress on Biotechnology in Animal Reproduction, 2002,
  6. ↑ Deepika Malayalam daily Newspaper dated 23 June 1996.
  7. ↑ A. Nyboe Andersen, L. Gianaroli, R. Felberbaum, J. de Mouzon and K.G. Nygren. Results generated from European registers by ESHRE Assisted reproductive technology in Europe, 2001
  8. ↑ "Genetics & IVF Institute". Givf.com. Archived from the original on 6 December 2012. Retrieved 27 July 2009.
  9. 1 2 Wennerholm, U. -B.; Soderstrom-Anttila, V.; Bergh, C.; Aittomaki, K.; Hazekamp, J.; Nygren, K. -G.; Selbing, A.; Loft, A. (2009). "Children born after cryopreservation of embryos or oocytes: A systematic review of outcome data". Human Reproduction. 24 (9): 2158–2172. doi: 10.1093/humrep/dep125 . PMID   19458318.
  10. 1 2 Evans, J.; Hannan, N. J.; Edgell, T. A.; Vollenhoven, B. J.; Lutjen, P. J.; Osianlis, T.; Salamonsen, L. A.; Rombauts, L. J. F. (2014). "Fresh versus frozen embryo transfer: backing clinical decisions with scientific and clinical evidence". Human Reproduction Update. 20 (6): 808–821. doi: 10.1093/humupd/dmu027 . ISSN   1355-4786. PMID   24916455.
  11. ↑ Wikland M, Hardarson T, Hillensjö T, et al. (May 2010). "Obstetric outcomes after transfer of vitrified blastocysts". Hum Reprod. 25 (7): 1699–707. doi: 10.1093/humrep/deq117 . PMID   20472913.
  12. 1 2 3 Riggs R; Mayer J; Dowling-Lacey D; Chi TF; Jones E; Oehninger S (November 2008). "Does storage time influence postthaw survival and pregnancy outcome? An analysis of 11,768 cryopreserved human embryos". Fertil. Steril. 93 (1): 109–15. doi: 10.1016/j.fertnstert.2008.09.084 . PMID   19027110.
  13. ↑ "Baby born from 27-year-old donated embryo sets record". NBC News . 3 December 2020.
  14. ↑ Courbiere, B.; Decanter, C.; Bringer-Deutsch, S.; Rives, N.; Mirallie, S.; Pech, J. C.; De Ziegler, D.; Carre-Pigeon, F.; May-Panloup, P.; Sifer, C.; Amice, V.; Schweitzer, T.; Porcu-Buisson, G.; Poirot, C. (2013). "Emergency IVF for embryo freezing to preserve female fertility: A French multicentre cohort study". Human Reproduction. 28 (9): 2381–8. doi: 10.1093/humrep/det268 . PMID   23832792.
  15. ↑ Extension given for embryo storage [ dead link ] Google News. Retrieved on 11 September 2009
  16. 1 2 3 4 5 Zhang, Sarah (21 December 2017). "A 26-Year-Old Gave Birth From an Embryo Frozen for 24 Years". The Atlantic. Retrieved 14 October 2021.
  17. ↑ "Meet Molly, the baby who came from an embryo frozen when her mom was a year old". Washington Post. ISSN   0190-8286 . Retrieved 14 October 2021.
  18. ↑ AP News, February 1985
  19. ↑ Mukerji S., Mukherjee S., Bhattacharya, S.K. Indian J. Cryog., 1978, 3, 80.
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  21. ↑ Dhawale A.J. Dr Subhas Mukherjee and India's first test tube baby. PharmaTutor. 2014. V.2 N.12. P.99-106.
  22. 1 2 3 "Same-sex couples and singles use of fertility treatment hits UK record". Reuters. 9 May 2019. Retrieved 14 October 2021.
  23. 1 2 3 Debele, Gary (24 September 2018). "Legal Issues Surrounding Embryos and Gametes: What Family Law Practitioners Need to Know" (PDF). Journal of the American Academy of Matrimonial Lawyers. 31: 68. Archived from the original (PDF) on 24 October 2021. Retrieved 4 November 2021.
  24. 1 2 Szafranski v. Dunston, vol. 34, 12 June 2015, p. 1132, retrieved 21 October 2021
  25. ↑ "750 ILCS 46/ Illinois Parentage Act of 2015". www.ilga.gov. Retrieved 21 October 2021.
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