- All the eggs that a woman will ever have are produced by about six months of age while she is still in her mother’s uterus. No new eggs are produced after this time. At six months, there are about 4-5 million eggs. The number has declined to 1-2 million at birth, and by puberty there are less than one million eggs. The number of eggs rapidly declines. At the time of menopause, only a miniscule number of eggs remain. Not only does the number of eggs decrease, but the quality of eggs also are compromised by genetic changes, either chromosomal breaks or more subtle genetic changes. Therefore, in women over 40, the pregnancy rate declines dramatically and the spontaneous abortion rare increases. Some studies show the abortion rate in over 40 women to be over 50 %.
In order to compensate for the decreasing embryo quality, many clinics transfer a larger number of embryos (more than 4) to the uterus in an effort to off-set the quality problems by providing more embryos for implantation. The less healthy embryos will be rejected, favoring implantation of the healthy ones.
Number of Embryos available for Transfer to the Uterus
- As the woman ages, the response to fertility drugs decreases, and thus the number of embryos available for transfer to the uterus.
- Pelvic disease due to chronic inflammation, previous surgery, or severe pelvic endometriosis may result in a reduction in the amount of functional ovarian tissue available. This could influence ovarian response to hormones that induce ovulation and accordingly the potential to produce an optimal number of eggs for IVF/ET.
- The presence of uterine fibroids (a benign type of uterine tumor), are more common in older women. If present, may need removal before resorting to one of the assisted reproductive technologies.
- Sperm quality is a major factor which influences the likelihood that eggs can be successfully fertilized in vitro. Except in very old age, sperm quality is not age related. Low sperm counts aren’t as much of a factor as the morphology of the sperm itself. While normal morphology is important, DNA fragmentation testing is also done to test the overall sperm quality. This testing will test the overall DNA quality to see if it is healthy enough to conceive a child.
Call (919) 233-1680 or