In vitro fertilization (IVF) is a form of assisted reproductive technology in which laboratory fertilized eggs (embryos) are being implanted into a woman’s uterus for further pregnancy. The technique has a higher success rate in women under the age of 40. The success rates dramatically increase for older women, because of the oocyte poor quality.
Study of Dr. Yanguang Wu, embryologist and associate scientist at the Centre for Human Reproduction in New York, NY, and colleagues found that aging of the eggs’ environment is the problem, not aging of the eggs themselves.
Older women were found to be significantly more likely to experience early luteinization, which prevents the ovaries from maturing oocytes and preparing the womb for pregnancy, so the chance of conception is reduced. This occurs due to aged environment inside an older woman’s body.
“The chances of reversing damage to an egg are practically zero and so these findings are exciting because it’s much more hopeful to therapeutically target the egg’s supporting environment,” Dr. Wu declared.
Following the study results, the team found that earlier harvesting of oocytes can result in better IVF success rates, by administering hCG when the oocyte follicle is only 16 mm, earlier than the usual 19-21 mm method. At this moment,the risk of luteinization is lower, when fertilizing older women.
The new approach led to increased production of good quality embryos an higher success rates when compared to the conventional IVF method. Dr. Wu declared: “We do believe our study would benefit IVF outcome in older women because from our study, by retrieving oocytes earlier from smaller follicles, the negative effects of early luteinization were reduced, which results in a significant increase of oocyte/embryo quality and pregnancy rate.”
Larger studies are further necessary to test the efficacy of the new fertilization approach, but scientists believe that the tests will also help finding if the new method can improve the fertility treatments in younger women too.