It has been disclosed that an Osaka woman in her 40s gave birth to a baby last year using her own frozen egg in what is believed to be the first such case in Japan involving a healthy woman. In 2014, it was reported that a 30-year-old woman gave birth to a child using an egg she had frozen 12 years earlier when she was undergoing cancer treatment that could have made her unable to reproduce.

Egg-freezing technology is drawing increased interest as a growing number of working women marry and give birth at later ages. Births using frozen eggs may increase. Still, the method involves a variety of risks. If the option is being pursued because women want to put off childbirth to avoid facing problems in their jobs, it shows the need for creating a socioeconomic environment in which women can have children at a younger age without disrupting their careers so they don’t feel forced to rely on technology that has a low success rate.

In the process of freezing eggs, oocytes (immature egg cells) are extracted from the woman. It used to be difficult to freeze and store oocytes because they are easily damaged compared with sperm or fertilized eggs. But recent technological advances have made egg preservation a viable option for people who need to undergo cancer or other treatment that will damage their ovaries but may want to have children in the future. Freezing their eggs certainly gives these women hope.

But there are also women who have begun to rely on the method because they’re too busy or don’t want to jeopardize their careers by having children, or have not yet found a partner but want to have children when they do. The Osaka woman was in the latter category. The chances of becoming pregnant decrease as women reach their late 30s due to the aging of their eggs. If women have their eggs frozen at an earlier date, the chances of them being able to have a child later in life increase. Interest is growing in this method as more Japanese women marry and give birth at later ages. In 2013 these figures were 29.3 and 30.4, respectively — about four years later than in 1980, according to a 2015 government report.

The Osaka woman had her eggs frozen on several occasions before she got married, thawed the eggs in 2014 and became pregnant through in vitro fertilization (IVF) using her husband’s sperm. But her outcome should be seen as luck. The track record of the Osaka clinic shows that chances of becoming pregnant by using frozen eggs are not high. The clinic has frozen eggs from some 230 healthy women since 2010. Of the 17 women who went through an IVF procedure, only the Osaka woman succeeded in becoming pregnant and giving birth.

The success rate of IVF itself is low. In addition, the pregnancy rate drops further if the eggs used are from older women. Even if such eggs are successfully fertilized, the functions of the uterus and other organs weaken as women age, reducing the chance of a successful birth. If women give birth at an advanced age, the medical risks to their bodies and babies are higher compared to those of younger women. The process of extracting eggs also puts women at risk of adverse reactions as they must take drugs to stimulate ovulation and then undergo an invasive procedure to harvest the eggs. The total cost of extraction, freezing, storage of eggs and the IVF procedure is also quite high — the Osaka woman reportedly paid ¥300,000 to ¥500,000 for one round of egg extraction — because the procedure is not covered by public health insurance. Despite the risks involved in freezing eggs, however, some local governments and businesses are financially supporting women who want to use the method.

Medical societies have expressed mixed views on the method. A panel under the Japan Society of Obstetrics and Gynecology last year said that it does not recommend freezing eggs for future pregnancy regardless of the woman’s age, citing the risk of complications such as hypertension and noting that the possible effects on the health of babies born from frozen eggs remain uncertain. One panel member asserted that the availability of egg-freezing technology could lead women to postpone childbirth. In 2014, the same society allowed egg-freezing for women who are certain to lose ovarian functions due to cancer treatment or radiation therapy. In 2013, the Japan Society for Reproductive Medicine issued a guideline allowing egg-freezing for women below the age of 40, including those who have no health problems, citing technological advances.

The right of women to have their eggs frozen should be respected. The important thing is that they do so by fully taking into consideration the method’s advantages and risks. Medical societies and associations should collect relevant data and present reliable information on various aspects of egg-freezing, including the success rate, risks and cost so that women can fully understand the method and make an informed decision.

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