An experimental technique has allowed a woman to successfully have two children after chemotherapy, several newspapers have reported.
The mother, Dr Stinne Bergholdt of Denmark, had part of her right ovary removed and frozen prior to chemotherapy for a rare bone cancer. Although the powerful anti-cancer drugs made her infertile, she was later able to conceive two children once the frozen tissue was thawed and re-implanted. Dr Bergholdt and her two daughters, born in 2007 and in 2008, are reported to be healthy.
This research is encouraging as it is said to be the first time that a woman has had two separate pregnancies following the transplant of 'frozen and thawed' ovarian tissue. Dr Bergholdt’s doctor, Professor Claus Yding Andersen, told The Times that the result “should encourage the development of this technique as a clinical procedure for girls and young women facing treatment that could damage their ovaries”.
However, it is important to remember that this is only a single case, and questions remain over how successful or safe this technique might be for other women. Only time will tell whether further cases of ovarian tissue re-implantation will be as successful as in this interesting but very early research.
Where did the story come from?
This report was written by the subject of this case study, Dr Stinne Bergholdt, and her colleagues from Aarhus University Hospital, University Hospital of Odense and University Hospital of Copenhagen in Denmark. The research was funded by the Danish Cancer Foundation Grant and reported in the peer-reviewed medical journal Human Reproduction.
This research has been accurately represented across the press.
What kind of research was this?
This was a case report on a mother’s two separate, successful pregnancies that occurred following the re-implantation of cryogenically preserved ovarian tissue. This tissue was frozen prior to chemotherapy, a treatment that can cause permanent infertility.
As a single case report, this research must be considered in the correct context: simply as a single case. Reports based on a single case cannot provide us with clear answers of whether the result is a one-off occurrence or whether similar results could be replicated numerous times over.
Another limitation of single case reports is that they are not able to fully inform on any possible risks or harms of experimental treatments such as ovarian tissue cryopreservation. They also cannot assess who would be the most suitable candidates for such a technique.
What is the background?
Dr Stinne Bergholdt was 27 years old when she was diagnosed with the rare bone cancer, Ewing’s sarcoma. She had previously had her entire left ovary removed due to an unrelated problem (a dermoid cyst). Prior to starting any chemotherapy, which would be harmful to her remaining ovary, approximately one-third of the right ovary was surgically removed in 2004. The tissue was split into 13 pieces then cryopreserved (frozen in controlled conditions). Dr Bergholdt’s cancer treatment then involved six courses of chemotherapy, surgical removal of the remaining cancerous sites and three final courses of chemotherapy.
After completion of her treatment, she had symptoms consistent with menopause. Examination of the tissue in her right ovary confirmed that following chemotherapy Dr Bergholdt had no remaining ovarian follicles (follicles can develop into mature egg cells.
Six pieces of ovarian tissue (around 15–20% of an entire ovary) were thawed and then re-implanted into Dr Bergholdt’s remaining right ovary in December 2005.
What was the outcome?
After re-implantation, Dr Bergholdt’s hormone levels began to climb back to pre-menopausal levels. Dr Bergholdt conceived her first daughter following a form of mild ovarian stimulation that encourages the ovary to release mature eggs. The first healthy baby girl was born by caesarean section on 8 February 2007. The mother returned to the fertility clinic in January 2008 for IVF treatment. However, a pregnancy test revealed that she had naturally conceived again.
After a second complication-free pregnancy, the second healthy baby girl was delivered on 23 September 2008. At the time of writing this case report (a full four years after re-implantation) the ovarian tissue remained functional.
How did the researchers interpret the results?
The authors say this is the first case of a woman giving birth to two healthy children from two separate pregnancies following re-implantation of frozen then thawed ovarian tissue. The results showed that, in a woman who had experienced a chemotherapy-induced menopause, just 15-20% of one ovary could result in the production of fully mature egg cells for a period exceeding four years and that “the capacity to give birth to healthy children remains”.
As the authors say, this recent success raises the number of children born as a result of re-implanting frozen then thawed ovarian tissue to nine, globally. Six were conceived with the help of IVF and three conceived naturally. This is undoubtedly encouraging news but it remains a very small number of cases.
Given the extremely small number of women that have given birth using this technique, many questions remain over which women would be the most suitable candidates and which would be most likely to achieve success. Further research is needed to establish how successful further ovarian re-transplants are in a greater number of women and whether there are any adverse health risks to the mother or the child. There is no indication in this report of how many additional women have previously been unsuccessfully treated, alongside the successes.
As Dr Melanie Davies, a spokesperson for the Royal College of Obstetricians and Gynaecologists, says, this is “very encouraging news” but it is still "early days". However, given the importance of preserving the fertility of chemotherapy patients, this technique will undoubtedly be the focus of larger studies in the future. These may be able to answer some of the important questions that surround new experimental treatments and provide a fuller picture of the potential of this technology.