Wednesday, July 29, 2009

WFWW-Implantation Question

Ask Dr. Wisot

Questions from the reproductivepartners.com bulletin board

Q. When does implantation take place in IVF?

I have had IVF with blastocysts (5 day old embryos) implanted. When the blastocyst is placed in the uterus what stops it from falling out? And when would implantation occur? Immediately? Also, what criteria are used to judge the quality of blastocysts?

A. Embryos are sticky and can adhere to the surface of the uterine lining before they actually implant, which helps prevent them from “falling out.” In addition, we now use a substance in the fluid used to transfer the embryos to make it the same viscosity as fluid in the uterine lining, which prevents migration of the embryos in IVF. That’s so-called “embryo glue,” although it is not really a glue. Despite these measures, the embryos can float around somewhat, and that's why we want activity restricted for 48 hours after an IVF embryo transfer.

Implantation is defined as the process by which an embryo attaches to the uterine wall and penetrates the surface and the circulatory system of the mother. It starts between six to ten days after ovulation in natural conceptions, or egg retrieval in IVF, no matter how and when the embryos reach the uterus. Usually the degree of development of the embryo will determine when the process will actually begin. Most of the time, implantation occurs silently. There are no consistent signs or symptoms associated with it except that it occasionally can result in some vaginal spotting or bleeding which may be mistaken for the start of the next menstrual period.

In IVF, blastocysts are generally graded on the stage of their general development on a one to six scale, and the specific development of what will become the fetus and the placenta on A-B-C scales (A being best). Blastocysts graded at 3AA or higher would generally be considered good quality blastocysts, although this grading level is not required to create a healthy pregnancy. Many healthy babies have been born from embryos which have only reached the stage before blastocyst (morula) after five days of development. Of course none of this is known in a pregnancy conceived by conventional means as we have no idea of what was happening to that embryo, although they would be going through much the same process.

Arthur L. Wisot, M. D.
Reproductive Partners Medical Group, Inc.
Southern California

Wednesday, July 22, 2009

Do blastocysts like fresh air?

WFWW-Do blastocysts like fresh air?

Embryos are very sensitive to their environment. Issues such as temperature, light and atmosphere are critical to proper embryo development and thus to a center’s success rates.

A study in the June 2009 issue of the journal “Fertility and Sterility” supports our decision at Reproductive Partners some time ago to use low oxygen incubators. In this study blastocysts were cultured in atmospheres with either 6% carbon dioxide (CO2) in air, the equivalent to 19% O2, a two-gas system; or 5% O2, 6% CO2, and 90% nitrogen (N2), a three-gas system.

Three hundred ninety six women, were randomized to 197 cultures with the three-gas system and 199 cultures with the two-gas system. The outcome with the three-gas system compared with the two-gas system showed a statistically significantly increased blastocyst rate (47.8% vs. 42.1%), mean number of blastocysts (3.8 vs. 3.3), and number of cryopreserved blastocysts (1.7 vs. 1.1). The mean number of transferred blastocysts was 1.2 versus 1.3. Culture with the three-gas system increased the relative birth rate by 10% compared with the two-gas system (42% vs. 32%, respectively), a statistically significant difference. The overall twin rate was 4.8%.
They concluded that blastocyst culture with low-oxygen (5%) versus high-oxygen (19%) concentration yielded a better blastocyst outcome and a marked improvement in birth rate.

Wednesday, July 15, 2009

WFWW-PGD for Single Gene Defects

Wisdom from Wisot Wednesday

What Do Women at High Risk for Genetic Diseases Think of PGD?

PGD is an IVF technology that can detect chromosomal abnormalities in the embryos of women at high risk for anuploidy, as well as single gene defects in the those of couples who carry the gene for a serious disease. One problem in applying this technology is that it is not widely known that it exists.

A survey reported in the journal “Fertility and Sterility” examined women’s attitudes about the technology at a national conference for individuals and families affected by hereditary breast and ovarian cancer.

Of the women surveyed, only 32% had ever heard of PGD before taking the survey. None of the women surveyed had actually used PGD, and 44% believed they would not use it in the future. However, 57% of attendees believed that PGD was an acceptable option for high-risk individuals, and 74% believed that high-risk individuals should be given information about PGD.
I am sure that if groups carrying genes for other single gene defect diseases such as cystic fibrosis, muscular dystrophy and Huntington’s Disease were surveyed, we would find the same lack of awareness of the technology.
The authors concluded that health care professionals who serve cancer patients should consider incorporating information about PGD into patient education. Further research is needed to survey physicians and genetic counselors about their knowledge and opinions of PGD. The same conclusion probably applies to couples carrying other single gene diseases.

Tuesday, July 7, 2009

WFWW-Gender Selection

Wisdom from Wisot Wednesdays

Can I do gender selection?

I have been an infertility patient with 2 successful frozen embryo transfers, one singleton and now a twin pregnancy, all 3 boys. I can't believe we are considering this already, but we've been throwing around the idea of trying again. I was wondering if I can do some procedure to do gender selection and look for any little girl embryos to transfer back.

There are two procedures you can take advantage of to try to increase your chances of a girl. One is sperm selection through a patented sperm selection technique called Microsort. This technique is 90% effective creating girl embryos; 70% success when boys are desired. It can be used with either intrauterine insemination or IVF depending on how many viable sperm of the desired sex are available after the separation process, as well as fertility issues in the intended parents.

If IVF is needed, as in your case, the process can be increased to virtually 100% accuracy by adding preimplantation genetic diagnosis (PGD) to select girl embryos. In addition to sorting the sperm to increase the number of girl embryos with Microsort, the embryos could be biopsied three days after retrieval and insemination. One cell is removed from the then six to eight cell embryos and sent to the genetics lab where from five to twelve chromosomes, including the sex chromosomes, will be examined. Chromosomally normal female embryos will be identified for transfer five days after retrieval.

There are some ethical issues related to this. First, Microsort is currently seeking FDA approval and their protocol requires that the procedure be performed for “family balancing.” That means a couple must have at least one child before seeking the procedure to balance with a child of the opposite sex. Second, if not enough sperm are available for insemination and IVF would be required for that reason only, the question of whether to do IVF, in others, just for sex selection raises an ethical dilemma since IVF is more risky, invasive and costly. If you want sex selection for whatever your situation, you will likely find differing answers among different doctors to all the ethical issues raised by sex selection.