Featured Research

from universities, journals, and other organizations

Researchers Identify Method That Produces Viable Eggs When Thawed

Date:
June 9, 2005
Source:
University Of Michigan Health System
Summary:
A new technique might allow women diagnosed with cancer the opportunity to have children when chemotherapy and radiation treatments rob them of their fertility, researchers at the University of Michigan Comprehensive Cancer Center have found.

By having her eggs frozen before she begins cancer treatments, a woman can preserve the hope of one day having a baby.
Credit: Image courtesy of University Of Michigan Health System

ANN ARBOR, MI - A new technique might allow women diagnosed with cancer the opportunity to have children when chemotherapy and radiation treatments rob them of their fertility, researchers at the University of Michigan Comprehensive Cancer Center have found.

By having her eggs frozen before she begins cancer treatments, a woman can preserve the hope of one day having a baby.

Freezing eggs is one thing; thawing them safely so they can lead to pregnancy is the challenge. In the past, efforts to freeze a woman's eggs, or oocytes, have not worked well because the cells are large. When the egg is thawed, ice crystals cause damage that prevents the egg from being fertilized.

U-M researchers looked beyond traditional techniques to a method of freezing cells called vitrification. This cryopreservation technique allows the eggs to be cooled fast enough that the transformation from liquid to solid is instantaneous. No ice crystals form and the consistency resembles a viscous glassy state. Research so far has used mouse oocytes but U-M expects to make the technology available in the clinic soon.

"With traditional slow-freeze techniques, just over half the eggs survive the thawing process. Using vitrification, we are getting 98 percent survival. For a woman with cancer, these are the only eggs she's ever going to have, so it's important that as many as possible remain viable," says Gary D. Smith, Ph.D., associate professor of obstetrics and gynecology, urology, and molecular and integrative physiology at the U-M Medical School, and director of the Fertility Counseling and Gamete Cryopreservation Program at the U-M Comprehensive Cancer Center.

Smith will present results of his research on Sunday, May 29, at the World Congress on In Vitro Fertilization, Assisted Reproduction and Genetics in Istanbul, Turkey.

Cancer treatments such as chemotherapy and radiation therapy can cause damage to a woman's reproductive system and leave her unable to have children afterward. Some women may regain their reproductive function after their treatment ends and may be able to conceive on their own, while others will become infertile. Egg cryopreservation could be insurance for those women at highest risk of fertility problems after cancer treatment.

When a woman wishes to become pregnant, the vitrified eggs would be warmed and then fertilized with male sperm. The fertilized eggs would then be transferred to the uterus in the same procedure that's used successfully when couples freeze embryos.

When eggs are warmed after vitrification, fertilization rates with conventional IVF are low. Instead, researchers have found, a single sperm cell must be injected into a single oocyte, a technique called intracytoplasmic sperm injection, or ICSI. While ICSI is an established technique used in assisted reproduction, it is more complex and costs more than traditional methods.

Using mouse oocytes, 80 percent of eggs that had been vitrified became fertilized with ICSI, with a live birth rate of about 30 percent, comparable to conventional IVF when eggs are not frozen. The fertilization and birth rates for vitrified eggs are similar to the rates for control eggs that were not vitrified.

For egg freezing to work, it must be a mature oocyte, which means a woman must have 14 days of hormone treatments to stimulate mature egg production. This could limit its applications for some women. Researchers question if it is appropriate for women with cancers fueled by estrogen, such as breast cancer. In addition, the hormone treatments require delaying the start of cancer therapy, which may not be an option for every patient.

Guidelines for patients and physicians still need to be established as the technique begins to be offered in a clinic setting, Smith says. "This is a very new technology and it requires education both of patients and physicians," Smith says.

U-M has cryopreserved eggs for one patient; however, the service is currently not offered while researchers seek approval for a clinical trial. A specialized clinic in the U-M Comprehensive Cancer Center provides counseling and information for women considering their fertility options, and the clinic currently freezes embryos for cancer patients who have a partner. The clinic also offers counseling and sperm freezing for male cancer patients. U-M will offer egg vitrification only to women facing cancer treatments, because the long-term safety of this technique remains unknown.

"In a woman with cancer, if she is going to lose her reproductive capacity because of cancer treatments, this is her only choice to have baby with her own eggs," Smith says. A clinical trial through the U-M Comprehensive Cancer Center is planned to begin by fall.

Funding for the research is from the U-M Department of Obstetrics and Gynecology.

For information about fertility counseling for cancer patients, visit www.cancer.med.umich.edu/clinic/fertilityclinic.htm or call the Cancer AnswerLine at 800-865-1125.

Reference: World Congress on In Vitro Fertilization, Assisted Reproduction and Genetics, May 26-29, 2005, Istanbul, Turkey


Story Source:

The above story is based on materials provided by University Of Michigan Health System. Note: Materials may be edited for content and length.


Cite This Page:

University Of Michigan Health System. "Researchers Identify Method That Produces Viable Eggs When Thawed." ScienceDaily. ScienceDaily, 9 June 2005. <www.sciencedaily.com/releases/2005/06/050607005228.htm>.
University Of Michigan Health System. (2005, June 9). Researchers Identify Method That Produces Viable Eggs When Thawed. ScienceDaily. Retrieved April 17, 2014 from www.sciencedaily.com/releases/2005/06/050607005228.htm
University Of Michigan Health System. "Researchers Identify Method That Produces Viable Eggs When Thawed." ScienceDaily. www.sciencedaily.com/releases/2005/06/050607005228.htm (accessed April 17, 2014).

Share This



More Health & Medicine News

Thursday, April 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Could Even Casual Marijuana Use Alter Your Brain?

Could Even Casual Marijuana Use Alter Your Brain?

Newsy (Apr. 16, 2014) A new study conducted by researchers at Northwestern and Harvard suggests even casual marijuana use can alter your brain. Video provided by Newsy
Powered by NewsLook.com
Thousands Of Vials Of SARS Virus Go Missing

Thousands Of Vials Of SARS Virus Go Missing

Newsy (Apr. 16, 2014) A research institute in Paris somehow misplaced more than 2,000 vials of the deadly SARS virus. Video provided by Newsy
Powered by NewsLook.com
Formerly Conjoined Twins Released From Dallas Hospital

Formerly Conjoined Twins Released From Dallas Hospital

Newsy (Apr. 16, 2014) Conjoined twins Emmett and Owen Ezell were separated by doctors in August. Now, nearly nine months later, they're being released from the hospital. Video provided by Newsy
Powered by NewsLook.com
Ebola Outbreak Now Linked To 121 Deaths

Ebola Outbreak Now Linked To 121 Deaths

Newsy (Apr. 15, 2014) The ebola virus outbreak in West Africa is now linked to 121 deaths. Health officials fear the virus will continue to spread in urban areas. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins