Recent studies have shown women 38-39 years old have a success rate of IVF 23.6%, while the 44 years of age and older have a success rate of only 1.3%.
Dr. Wu Yanguang, embryologist and scientific associate at the Center for Human Reproduction in New York, New York, and colleagues report their findings in the Journal of Endocrinology .
In vitro fertilization (IVF) is a form of assisted reproductive technology (ART). First, fertility medication is administered to stimulate a woman’s egg, or oocyte, production. The eggs are retrieved from the ovaries and combined with sperm in a laboratory dish for fertilization. The embryos are transferred to the woman’s uterus.
It is well established that IVF is more likely to be successful for women under 40. According to Dr. Wu and colleagues, recent studies have shown that women aged 38-39 have a success rate of IVF 23.6%, while the 44 years of age and older have a success rate of only 1.3%.
Previous research has shown that egg quality declines as a woman ages, reducing the likelihood that older women to conceive through IVF. However, the mechanisms behind this are unclear, Dr. Wu attributed to the lack of resources in clinical laboratories.
However, with the resources available at the Center for Human Reproduction, the team was able to take a closer look at what drives the reduction in egg quality in older women.
aging eggs environment is the problem, aging eggs themselves
The researchers compared the reproductive tissues of egg donors aged 21-29, 30-37 and 43-47 years.
Compared with egg donors 21-29 and 30-37 years old, to 43 to 47 years old had reduced growth and proliferation of granulosa cells – cells that support the oocytes within a woman ovarian and help its growth.
Further investigation revealed that the granulosa cells of older women produce less cellular receptors for follicle stimulating hormone (FSH), but produce more receptors for luteinizing hormone (LH) and Progesterone .
According to the authors, these changes in sensitivity to the hormone mean that older women are significantly more likely to experience premature luteinizing, preventing the ovaries of oocyte maturation and prepare the uterus for pregnancy.
The team explains the process luteinizing usually happens after ovulation , which increased LH levels in a decrease in FSH levels and increased progesterone levels. However, if the luteinizing occurs before the egg leaving the ovary, the probability of conception decreases.
Dr. Wu says these results show that it is not mature eggs who are responsible for the success of IVF lower among older women, but the environmental aging eggs that is to blame.
“The chances of reversing the damage to an egg are virtually zero and so these findings are very interesting because it is much more hopeful for therapeutically targeting egg supportive environment,” says Dr. Wu.
These results gave the team thought; could recover the oocytes before IVF process – before premature luteinizing – increasing success?
previous harvest oocytes result in better success rates of IVF
At present, doctors usually perform IVF wait for the follicles reach 19-21 mm of oocytes prior to administration of the hormone human chorionic gonadotropin (hCG) for “mature” oocytes, and prepares them for disposal.
In this study, however, Dr. Wu and colleagues IVF adopted an approach in which hCG was administered when follicles oocytes were 16 mm – at a point when the risk of early luteinization is less – enabling them retrieve oocytes when they were immature.
Comparison of the results of conventional IVF with their new approach, the team found early oocyte retrieval led to increased production of good quality embryos and higher success rates.
Dr. Wu said Medical News Today the team hopes their findings will improve pregnancy success in older women receiving IVF:
“We have our study would benefit outcome of IVF in older women because from our study, by recovering oocytes before smaller follicles, the negative effects of decreased early luteinisation, which results in a significant increase oocyte / embryo quality and pregnancy rate. “
Dr. Wu added that the effectiveness of the new approach to IVF needs to be tested in larger studies, and the team also hopes to test whether it could improve success rates of IVF in younger women.
Last month MNT reported on a study that found that many teenagers and young adults who are experiencing cancer therapy – which can adversely affect fertility – are aware of their options for fertility preservation .