Tag Archives: frozen embryos

Surrogate Pregnancy after transfer of Cryoshipped, Vitrified Human Blastocysts

Rotunda achieved its first pregnancy with Cryoshipped Vitrified embryos from USA and transferring them into a surrogate mother.

Till now, we have received frozen embryos from many countries and successfully transferred them into surrogate mothers at Rotunda. Most of these embryos were frozen by the slow freezing process. As vitrification is becoming popular as a method of choice for freezing gametes, we have started receiving vitrified embryos from world over. Our first case of cryoshipped, vitrified blastocyst transfer has resulted in a pregnancy.

A short history lesson:

In 1972 preimplantation mammalian embryos were first successfully cryopreserved. The method was very time consuming. Slow cooling was used (1 degree/min or less) to about -80 degrees Centigrade. Then the embryos were placed in liquid nitrogen.

The embryos also needed to be thawed slowly and a cryoprotectant added and removed in many gradual steps. This was a lot of work.

The first reported pregnancy in humans from frozen embryos was in 1983.

Most of the research has been done on mouse embryos. Development of frozen thawed mouse embryos, in vitro and in vivo, is not statistically reduced as compared to their nonfrozen counterparts.

Research continues in this area and human embryo freezing and thawing protocols have improved tremendously over the past 25 years. Hopefully, the newer vitrification technique will prove to have equivalent success rates with human blastocyst embryos transferred fresh or after freezing and thawing.

What is the difference between slow freezing and vitrification?

Patients who undergo IVF may have several eggs collected. The eggs are then fertilized with a sperm and checked for fertilization. Fertilized eggs are called embryos. A patient may have multiple high quality embryos eligible for embryo transfer back to the uterus. A certain number of embryos are chosen for embryo transfer, and the surplus of high quality embryos can be cryopreserved for future use.

Previously, embryos were cryopreserved using a slow freeze method. Embryos were run through different solutions of media toStorage of Cryopreserved embryosdehydrate the cells of water and replace it with cryoprotectant. Then the cryoprotected embryos were individually labeled and stored in cryopreservation straws, which were put in special freezers. These freezers slowly (-0.3 degrees Celsius per minute), cooled the embryos to -35 degrees Celsius using liquid nitrogen. They were then stored in liquid nitrogen (-196 degrees Celsius). At that extremely cold temperature, cellular activity is essentially brought to a halt, allowing the embryos to remain viable indefinitely.

When patients decide to use their cryopreserved embryos to try for a pregnancy, the embryos are removed from the liquid nitrogen, warmed and run through solutions of media to remove the cryoprotectant and rehydrate the cells with water. During cryopreservation, the formation of intracellular ice crystals can damage the cells of the embryo, decreasing future viability. Therefore, new methods were developed to improve cryopreservation techniques.

vitrification-hook 1Recent technical advancement in the field of cryobiology has opened up various options for freezing gametes and embryos at different developmental stages. The tendency of the IVF world to switch over to natural cycle IVF and to elective single-embryo transfer has put cryotechnology in the forefront of IVF. Vitrification method is gaining popularity as the method of choice for gamete/embryo cryopreservation.

Vitrification is a new process for cryopreserving embryos. Through vitrification, the water molecules in an embryo are removed and replaced with a higher concentration of cryoprotectant than in the slow freeze method. The embryos are then plunged directly into liquid nitrogen. This drastic (-12,000 degrees Celsius per minute) freezing creates a glass transition temperature, commonly called a “glass” state, and the embryos are vitrified. This quick freezing reduces the chance for intercellular ice crystals to be formed, thus decreasing the degeneration of cells upon thawing for embryo transfer.

In 1998, it was shown that vitrification using an EG-based vitrification solution (EFS40) (Kasai et al., 1990) with conventional cryo-straws was effective for human embryos at the 4- to 8-cell stage (Mukaida et al., 1998). The effectiveness of vitrification was confirmed for human embryos at the 8- to 16-cell stage (Saito et al., 2000) and the morula stage (Yokota et al., 2001b), also using EG-based solutions.

Many studies show survival rates of vitrified embryos to be far higher than survival rates of slow freeze embryos. Thus far at Rotunda, vitrification results are very encouraging, and we are excited to offer this cutting edge technology to our patients.

For more information about vitrification, ask to speak to the embryologist at your center.

Vitrification, a cutting edge technology for cryopreservation of embryos, is now available at Rotunda – Center for Human Reproduction.

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Birth of first UK baby screened for genetic breast cancer

The first baby to be screened for alterations in the breast cancer-causing gene, BRCA1, was born last week. The child was at risk from inheriting the gene from her father, who has women in three generations of his family who have been diagnosed with breast caner in their twenties as a result of inheriting the defective gene.

breast_cancer22 Paul Serhal, the fertility expert who treated the couple at the Assisted Conception unit of University College Hospital, London, said: ‘This little girl will not face the spectre of developing this genetic form of breast cancer or ovarian cancer in her adult life. The parents will have been spared the risk of inflicting this disease on their daughter. The lasting legacy is the eradication of the transmission of this form of cancer that has blighted these families for generations.’

The BRCA1 gene, when properly functioning, can help prevent breast cancer, but abnormal variations can significantly increase the risk of developing breast cancer. Females born with the affected gene face a 50-80 per cent risk of contacting breast cancer and a 40-60 per cent chance of developing ovarian cancer.

In 2006 the UK’s Human Fertilisation and Embryology Authority (HFEA) permitted fertility clinics to perform pre-implantation genetic diagnosis (PGD) – a procedure whereby embryos are tested for various conditions, the healthy ones are re-implanted and those that are affected are discarded – to test for this type of gene that makes carriers susceptible to a disease but that does not necessarily lead to disease in all cases. BRCA1 and BRCA2 account for around five per cent of breast cancers and it is thought that roughly 37,000 women in the UK carry BRCA1.

pgd1The couple concerned, who wish to remain anonymous, underwent IVF despite being fertile. A single cell was removed from the 11 embryos created when they were at the eight-cell stage and tested for the defective BRCA1 gene, revealing that only five of the embryos were free from the gene. Two of these were implanted into the mother’s womb, of which one, a girl, pgd21 successfully implanted to develop until birth.  The remaining three healthy embryos were frozen in case the parents want more children in the future. The six embryos carrying the defective BRCA1 gene were discarded.

Given that the breast cancer is increasingly curable and that carriers of the gene do not necessarily develop the disease (and vice versa), questions have been raised over the ethics of the procedure. Josephine Quintavalle, of the campaign group Comment on Reproductive Ethics (Core), told the BBC that she believes the procedure is a step too far, as it gives the message that ‘you are better off dead, than being born with this gene’. She added: ‘I hope 20 years down the line we will have eradicated breast cancer – not eradicated the carriers’.

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Fate of surplus frozen embryos : a difficult decision

Many infertility patients with unused frozen embryos are dissatisfied with the common options offered to them, such as donating to another couple or discarding the embryos, according to a study to be published Thursday in Fertility and Sterility, the New York Times reports. It is estimated that more than 400,000 embryos are frozen at clinics across the U.S., and many infertility patients grapple with the decision of what to do with embryos after they no longer want additional children, the Times reports.

 picture-25The study, which was conducted by researchers at Duke University Medical Center, involved a survey of more than 1,000 infertility patients at nine clinics (Grady, New York Times, 12/4). The survey found that donating embryos for research was the most popular option (Rubin, USA Today, 12/4). Among study participants who said they did not want any more children, 66% said they would be likely to donate their embryos for research, but only four of the nine clinics in the survey offered the option. Fifty-three percent of participants who wanted no additional children said they did not want to donate their unused embryos to other couples, mainly because they did not want their biological offspring to be raised by other people or have to address the possibility that their own children could encounter an unknown sibling in the future. In addition, 43% did not want their embryos discarded, and 20% said that their embryos likely would remain frozen indefinitely. Embryos can remain viable for 10 years or more if properly stored, although not all of them survive after thawing, the Times reports. According to the Times, a small number of study participants “wished for solutions that typically are not offered,” such as holding a ceremony during the thawing and disposal of the embryos or placing the embryos in the woman’s body at a time during her cycle when she was unlikely to become pregnant, so that they would “die naturally” (New York Times, 12/4).

 Lead author Anne Drapkin Lyerly — a bioethicist and associate professor of obstetrics and gynecology at Duke University — said a significant factor impeding embryo donation for research is the Bush administration’s 2001 restrictions on federal funding for research on new embryonic stem cell lines (USA Today, 12/4). Brigid Hogan, chair of the department of cell biology at Duke, said there is insufficient funding to fully research existing embryonic stem cell lines, leaving minimal use for the hundreds of thousands of embryos available. Hogan said, “Even if somebody said, ‘I’ve got 100 embryos I’m donating tomorrow,’ I think there are many places that would just say, ‘We don’t have the funding'” (Collins, Raleigh News and Observer, 12/4). Sean Tipton — a spokesperson for the American Society of Reproductive Medicine, which publishes Fertility and Sterility — said researchers are reluctant to accept embryos donated from other medical centers because of concerns about violating informed consent procedures. Lyerly added that the process of shipping frozen embryos also presents a challenge (USA Today, 12/4).

 Lyerly said, “The national debate presumes that if you care about and respect a human embryo, you would want that embryo to have a chance at life.” She added, “What we found was that people cared very much about what happened to their embryos, but one of their significant concerns was that their embryos not become children in families other than their own” (Collins, Denver Post, 12/3). Mark Sauer, director of the Center for Women’s Reproductive Care at Columbia University Medical Center, said choosing what to do with the leftover embryos is a “huge issue” for couples, adding that some patients ask to be given their leftover embryos, while others pay storage fees for years and years. The Times reports that some patients stop paying for storage and “disappear, leaving the clinic to decide whether to maintain the embryos for free or to get rid of them.” Sauer said patients who do that “would rather have you pull the trigger on the embryos. It’s like, ‘I don’t want another baby, but I don’t have it in me; I have too much guilt to tell you what to do, to have them discarded.'”

 According to Lyerly, many patients create as many embryos as possible to increase their chances of having a child. She added that more information needs to be given to patients early in the in vitro fertilization process to inform them of their options for unused embryos and letting them know that deciding what to do “may be difficult in ways you don’t anticipate.” She said that discussion about the embryos should be “revisited and not happen just at the time of embryo freezing, because people’s goals and their way of thinking about embryos change as time passes and they go through infertility treatment” (New York Times, 12/4).

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IVF successes break new reproductive ground

Despite IVF being used for thirty years, fertility treatments are still breaking new ground to assist couples struggling to conceive children – in multiples. Recently the first US babies conceived using frozen eggs were born in Minnesota and now quadruplets have been born in California to two mothers within a same-sex partnership.

After two unsuccessful IVF cycles and a miscarriage, Ceresa and Jonathan Caudill succeeded in having the first babies in Minnesota to be born from frozen eggs rather than embryos. In California, partners Karen Wesolowski, 42, and Martha Padgett, 38, underwent fertility treatments for between three and four years, spending roughly £35,000 on five cycles of IVF, before having the first reported quadruplets to ever be born two mothers when they each had twins using IVF embryos created from Padgett’s eggs and a sperm donor.

The egg-freezing technology which successfully led to the birth of the Caudill’s twin daughters is an imperfect science. The egg is the body’s largest cell and, unlike sperm and embryos, is predominantly composed of water which crystallises during the freezing process and can damage it. Experts hope that, once reliable, the technique could significantly help women to control their reproductive destinies. Researchers posture that the technology could impact reproductive choice in much the same way that the birth control pill did forty years ago. ‘For women who are sure they are going to go through menopause from cancer treatments, or for women in their mid-30s who don’t see a partner on the horizon, there really aren’t other options’, said Dr. Elizabeth Ginsberg, president-elect of the Society for Assisted Reproductive Technology (SART) and a fertility doctor in Boston.
According to Dr. Charles Coddington who heads the Mayo fertility clinic in Rochester, many couples like the Caudills do not wish to create more embryos than are required for implantation because they are uncomfortable with concept of unused leftover embryos. The Caudills used the remaining eggs, which had been frozen for research purposes, as a last resort.

The Mayo Clinic now offers egg-freezing to women, including those who wish to delay pregnancy, for double the price of frozen-embryo storage – at roughly £500 – and makes it clear that the success rates is much lower to conceive children using this method. Only half of frozen eggs survive the thawing process. Then 10-15 per cent of those thawed eggs successfully lead to live births where as frozen embryos have a 50 per cent chance of leading to a live birth at the clinic. They use a technique that removes much of the water in the eggs before slowly freezing them and later thaw them slowly returning the water to the eggs for re-absorption.

The California couple had attempted every possible IVF combination, using both of their eggs, and was ‘exhausted’. After five unsuccessful attempts they were just trying to hedge their bets to successfully have a single child but were delighted to learn that they were each pregnant and that they were both having twins. The two sets of twins were surprisingly born only 22 hours apart. The couple is ‘thrilled, knowing they’re all related and can help each other through life’.

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Frozen is better than fresh when it comes to transplanting embryos in IVF

Danish scientists found babies born after a frozen embryo was thawed and implanted had higher birth weights than those born from fresh embryos.  

The study of over 19,000 babies also found no added risk of birth defects.

A European fertility conference heard frozen embryo babies did better because only the most robust embryos survived the freezing and thawing process. Freezing embryos allows couples to have several cycles of treatment from one egg collection.

That means it cuts the amount of times women have to take ovarian stimulation drugs.

As doctors want to avoid multiple pregnancies, it is common for just one embryo – which has been fertilised in the lab – to be transferred into the womb, and the rest frozen.

In later cycles, a frozen embryo is thawed and implanted three to five days after ovulation, exactly the same way as fresh embryos are used.

While single embryo transfers are becoming increasingly common, the researchers said there was little data on the results of using frozen embryos.

But earlier mouse studies had shown a higher rate of behavioural and development problems in animals born from frozen embryos.

In this study, presented to the European Society for Human Reproduction and Embryology meeting in Barcelona, all 1,200 babies who had been born from frozen embryos between 1995 and 2006 in Denmark were compared to the 17,800 babies born from fresh embryos.

The data showed no increase in the rate of congenital malformations – which include conditions such as spina bifida and cleft palate.

Fewer frozen embryo babies were admitted to neonatal care units, but the researchers said this was probably because there was a higher rate of multiple births in the fresh embryo group.

In addition, pregnancies lasted slightly longer in the frozen embryo group, and babies were an average around 200 grams bigger.

There was also a lower proportion of low-birth weight babies weighing under 2,500 grams (5.5lbs) and fewer premature births, before 37 weeks.

Dr Anja Pinborg, who led the research, said: “We think the reason for the differences is probably positive selection of the embryos for frozen embryo replacement.

“Only the very top quality embryos survive the freezing and thawing process.

“And you only get pregnancies in patients with lots of good embryos to freeze.”

She added that by the ovarian stimulation patients have to go through in order to get fresh embryos could negatively influence a consequent pregnancy – something women using frozen embryos would not be affected by.

Dr Pinborg said: “The findings are reassuring.

“If our results continue to be positive, it can be accepted as a completely safe procedure, which can be used more frequently than it is currently.”

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