Ellen Carpenter helps her son Zachary put on his socks. The toddler… (Lloyd Fox, Baltimore Sun )
Ellen Carpenter delayed marriage until she found Mr. Right, but by that time she was 38 years old, making it much more difficult to have children.
After getting pregnant with the help of hormone injections, the Frederick County resident lost the baby — a girl with severe body malformations — in the first trimester. She explored other options and chose to use frozen eggs from a donor. Today, Carpenter is the mother of a rambunctious 18-month-old named Zachary.
A growing number of women are turning to frozen eggs to solve their fertility problems as the controversial procedure that long raised safety concerns slowly gains acceptance. Fertility clinics around the country are working to make frozen donor eggs more available to women, and advances in medical technology such as flash freezing have helped improve the procedure's success rate.
The American Society for Reproductive Medicine added its stamp of approval in October to the use of frozen eggs on a limited basis by declaring that the procedure is no longer considered experimental. The group found that successful pregnancy rates were the same using frozen eggs as fresh eggs.
But frozen egg use still raises concerns and may not become mainstream any time soon.
Even as the medical society endorsed the procedure, it warned against widespread use, noting that its newness made it impossible to track long-term complications to the child. Questions abound about whether the freezing method contaminates the egg, whether it may cause health problems later in a child's life and how long frozen eggs may remain vital.
The society's findings came from examining the outcomes of 1,000 babies born to mothers who used frozen eggs — a sample too small to recommend the use of frozen eggs for everyone, its members said.
The group recommended it for women facing infertility because of chemotherapy and other medical procedures under which a woman's eggs deteriorate. They also approve of the limited use of frozen donor eggs for women like Carpenter who have trouble getting pregnant.
The group remains opposed to the growing practice of women freezing their eggs because they aren't ready for children and fret about future infertility.
"We don't know about so many things," said Dr. Samantha Pfeifer, chairwoman of the society's committee that came up with the recommendation. "What happens in older women? How long can you freeze eggs? It is too premature for everyone to be doing this."
Other critics worry that even with the warnings, more younger women, such as those focused on careers, will go through with the procedure, and fertility clinics will market more routine use of frozen eggs before additional research is done to determine long-term effects. They also warn that in vitro fertilization, with fresh or frozen eggs, comes with health consequences that many women don't think about.
"Egg retrieval is not a walk in the park," said Marcy Darnovsky, associate executive director of the Center for Genetics and Society in Berkeley, Calif. "Women don't look at that when they are doing what they can to have a child."
The expensive procedure doesn't always work. The high doses of hormones used for in vitro fertilization can lead to disorders, such as severe ovarian hyperstimulation syndrome, which causes excessive weight gain, difficulty breathing and even death, Darnovsky said.
The use of frozen eggs has been around since the 1980s, but only in the last decade has it become more reliable. Much of the improvement has come because of a new flash-freezing technique called vitrification. The procedure prevents the formation of ice crystals, which often develop during slow freezing and damage eggs.
However, chemicals are used to remove water from the egg before it is frozen. Darnovksy and others said there isn't research on whether the chemicals get absorbed in the embryo or egg.
For women using donor eggs, the transfer of a frozen egg into a women's body can be less complicated than that of a fresh egg. With fresh eggs the menstrual cycles of the women donating and receiving have to be synchronized through the use of birth control. Then the eggs are retrieved from the donor, fertilized with sperm and implanted into the mother's womb.
The use of frozen eggs removes the need for synchronization, which may take a couple of months. The frozen egg is simply fertilized with sperm and placed into the woman's womb. The procedure also costs less. A traditional fresh-egg donor cycle can cost $25,000 to $38,000, while using frozen eggs can cost about half as much.
Carpenter said she was attracted to the use of frozen eggs because of the simplified procedure. After losing a baby, she was looking for the least stressful alternative.
"We had a very healthy boy — 9 pounds, 11 ounces," Carpenter said. "I wanted to be a mother more than anything, and frozen eggs helped me get pregnant."