提供卵による５０才以上の妊娠は問題ない

南カリフォルニア大学の研究によると、健康に問題のない５０才以上の婦人は、提供卵により若い婦人と同様の成功率が得られ禁止する必要はないという。糖尿病や妊娠中毒症を発症しやすいとか帝王切開が増えるという問題はあるが、好ましい結果を期待できると結論した。

Test-Tube Pregnancy OK for Some Women Over 50
Tue Nov 12,10:34 AM ET
NEW YORK (Reuters Health) - Age alone shouldn't bar a woman from using donated eggs to become pregnant, the results of a small study suggest.
Women aged 50 and older who are "appropriately screened" can conceive by egg donation and have similar success rates to younger women who undergo the same procedure, although they do face a higher rate of certain pregnancy complications, Dr. Richard J. Paulson of the Keck School of Medicine of the University of Southern California, Los Angeles, and colleagues report.
The researchers base their recommendation on a study of 77 postmenopausal women who underwent in vitro fertilization (IVF) with the aid of donated eggs at their clinic between 1991 and 2001.
"There were 55 clinical pregnancies for a total pregnancy rate of 45.5%" and "there were no maternal or neonatal deaths," the authors write in the November 13th issue of the Journal of the American Medical Association (news - web sites).
Women in their 50s gave birth to singletons, twins or triplets in ratios similar to those of younger women who conceived by IVF. Older women were no more likely than younger women to deliver their babies prematurely or to have low birth weight infants. But the older women were more likely to undergo a cesarean section as opposed to vaginal delivery.
"On the basis of these data, there does not appear to be any definitive medical reason for excluding these women from attempting pregnancy on the basis of age alone," Paulson and colleagues write.
However, the authors note that during pregnancy, women over 50 were two to five times more likely to develop gestational diabetes than younger women. Thirty-five percent of the women in their 50s developed preeclampsia, a rate also several times higher than that seen among younger women.
Preeclampsia is a pregnancy complication marked by high blood pressure and swelling in the legs that affects as many as 1 in 10 women pregnant for the first time. If left untreated, it can develop into eclampsia, a life-threatening condition in which a woman has convulsive seizures in late pregnancy or during the first week after delivery.
Gestational diabetes, on the other hand, is a temporary condition in which a pregnant woman fails to produce enough insulin to keep her blood sugar in check. This increases the risk that a woman will have an extremely heavy baby, which can cause newborn fractures and breathing problems in the infant, as well as a difficult delivery for the mother.
But with "contemporary obstetric surveillance and management," Paulson's team concludes, "favorable maternal and neonatal outcome may be expected" for women over 50 who conceive by IVF.
SOURCE: Journal of the American Medical Association 2002;288:2320-2323.