JAPAN - At least 130 children were born in Japan through in vitro fertilization using eggs donated abroad by third parties in the five years from 2007, according to a survey conducted by The Yomiuri Shimbun.
In such cases, women visited foreign countries such as the United States to receive donated ova.
The ova were fertilized in vitro with their husbands' sperm, the fertilized eggs were implanted in the women, and the women then came back to Japan to give birth.
At least 90 such cases were reported in the period, according to the survey.
The average age of the women was 45, and the oldest woman was 58.
About 90 per cent of the cases were considered high-risk pregnancies or deliveries calling for special medical supervision.
Japan has no established system for in vitro fertilization using donated eggs.
Because few medical institutions are able to offer such treatments here, couples who desperately wanted children are believed to have gone abroad to seek ova from third parties with the help of brokers.
The Yomiuri Shimbun's survey was the first of its kind in Japan, as the government has not studied the phenomenon of women going abroad to seek ova.
There is also no domestic law stipulating the relationship between babies and mothers who give birth to them but do not have genetic links.
As the number of such women is expected to grow, observers are concerned about the government's delay in addressing the issue, including discussions on how such treatments should be carried out in Japan.
In the United States, in vitro fertilization using donated eggs is a more established fertility treatment.
In contrast, only six medical institutions in Japan have disclosed that they conducted in vitro fertilization using donated eggs.
Couples seeking the treatment face various difficulties, such as finding donors by themselves.
The survey was conducted on core and regional perinatal centers that treat women suffering from serious conditions in the perinatal period.
Questionnaires were sent to 367 such centers in March, and 238 of them responded.
Among the 238 institutions, 38 reported 106 cases involving childbirth resulting from in vitro fertilization using eggs donated by third parties over the five years from 2007.
The institutions based the numbers on such data as explanations from the mothers.
93 cases known in detail
Details, such as the ages of the mothers, were given for 93 of the 106 cases. The 93 cases resulted in the births of 135 children.
The countries women visited to obtain ova were disclosed in 66 of the 93 cases, which resulted in the births of 98 babies.
Fifty-six women went to the United States, six to Thailand, three to South Korea and one to Malaysia.
In 24 of the 93 cases, which resulted in the births of 32 babies, the in vitro fertilization took place abroad, but the foreign countries where the women obtained ova was unknown.
In the remaining three of the 93 cases, resulting in the births of five babies, it was not clear whether the mothers had gone abroad to receive ova from third parties.
By age, most of the 93 mothers were in their late 40s or older. Forty-three of them (46 per cent) were in their late 40s, while 21 mothers (23 per cent) were in their 50s.
The medical risks they faced were high. Symptoms such as hypertension in pregnancy, which endangers mothers and fetuses, and obstetric hemorrhage were reported in 82 of the 93 cases (88 per cent).
Among the 93 cases, premature delivery - childbirth before the 37th week of pregnancy - was reported in 42 cases (45 per cent). Childbirth by cesarean section was reported in 79 of the 93 cases (85 per cent).
Mothers cited aging, menopause and prolonged failure of other fertility treatments as reasons they sought in vitro fertilization abroad with donated ova in 68 of the 93 cases.
Reasons were also given for late maternity. Nine mothers cited premature menopause - menopause before the age of 40 - as their reason, and eight mothers cited cancer treatments, congenital diseases or removal of their ovaries.
Yasunori Yoshimura, chairman of the Japan Society for Reproductive Medicine, said it is necessary to prepare laws to deal with women going abroad for in vitro fertilization using third-party donor eggs.
"The government needs to develop legal systems as soon as possible," said Yoshimura, also a Keio University professor.
The lack of clear, relevant legislation could cause trouble regarding property inheritance. There are also issues regarding how to respond to children seeking to know their genetic mothers.
Masao Nakabayashi, director of Aiiku Hospital in Minato Ward, Tokyo, said the actual number of women who went overseas for in vitro fertilization using donated eggs could be several times the figure revealed in the survey, as many women may have chosen not to share the fact with their doctors.