Increasing the success rate

Developments in preimplantation control bring the stork closer to us.

PRE-IMPLANTATION GENETIC DIAGNOSIS

Pre-implantation genetic diagnosis is divided into the classic (PGD), which is used for fertile couples but carriers of your genetics, and genetic screening (PGS) for infertile couples. Classic pre-implantation diagnosis is useful for couples who suffer from or are carriers of a hereditary disease or already have a child suffering from a genetic disease, such as Mediterranean anemia, cystic fibrosis, hyotonic dystrophy, Duchenne disease and other rare genetic diseases. Pre-implantation genetic screening is aimed at infertile couples who have already undergone repeated failed IVF attempts, who suffer from regular miscarriages or where the man suffers from a severe form of reduced sperm quality. Until recently, preimplantation diagnosis was made in embryos that were on the 3rd day of their development with the so-called FISH method. By opening a small laser opening in the outer protective covering of the embryo (biopsy), at the 8-cell stage, a blastomere was removed and the embryo was then genetically tested for 10 chromosomes. The disadvantage was that on the one hand the 10 chromosomes were not representative of the whole, and on the other hand that 20% of the embryos at these early stages are mosaic, which means that they can have smooth and abnormal cells and are in a phase of reprogramming. In this way there was a risk that a cell that was abnormal would be biopsied and analyzed, even though the rest was normal, and thus an embryo would be labeled abnormal and discarded when it was genetically normal.

A IMPORTANT DEVELOPMENT

Recently, with the “Assisting Nature” Model Gynecological Center-Assisted Reproduction Unit at the forefront of research, pre-implantation diagnosis is carried out at the blastocyst stage and genetic analysis is carried out with a new method, called CGH. The advantage is that it becomes possible to analyze all 23 chromosomes that the fetus inherits from the parents and furthermore the result is known within 24 hours. Thus, embryo transfer can be done the next day in the morning, while pregnancy rates increase to 70%, since only genetically healthy embryos are transferred. The new method, of course, also has disadvantages, such as the cost, which ranges at 2,000 E, as well as the fact that many embryos do not manage to reach the blastocyst stage. In this factor, however, the quality of the laboratory plays an important role. In recent years, the contribution of “Assisting Nature” researchers to the improvement of blastocyst culture conditions is great.

It happens, several times. The reasons are not known, but most likely, the different psychology and the reduction of stress experienced by these women are responsible.

The average length of the cycle is 28 days, but it can vary between 21 and 35 days. The first half of the cycle before ovulation is called the follicular phase of the cycle and its diarrhea varies from cycle to cycle and from woman to woman, while the second half after ovulation, called the luteal phase, is always constant and lasts 14 days. Because most women have a 28-day cycle it has become common to believe that ovulation occurs on the 14th day (28-14=14). This is wrong because if we have a 35-day cycle, ovulation is on the 21st day (35-14=21), while if we have a 21-day cycle, ovulation occurs on the 7th day already (21-14=7)!

Quite simply, the woman is monitored with an ultrasound and hormonal blood test during her cycle (about three times) and as soon as her dominant follicle exceeds 16 mm, a single dose of HCG is administered at night, so that the egg contained within the follicle , to mature. Then, the following day, in the morning, the woman comes to the unit and only with local anesthesia is the egg retrieved. Immediately afterwards she can return to her work without the slightest discomfort. Once the egg is found and fertilized (by 80%), the embryo is transferred to the uterus on the 3rd or 5th day of culture.

Human reproduction is the result of the union of the sperm with the egg. Their union will result in the embryo that will develop in the uterus to give birth to the child. The egg lives for only 24 hours. If intercourse occurs on fertile days, the sperm is deposited in the vagina and lives for about 3 days. Therefore, the fertile day, although in the strict sense of the term, is only one, due to the long lifespan of the sperm and the relative instability of ovulation, the 6-7 days around ovulation are counted as fertile-dangerous days.

The sperm through the vagina, cervix and uterine cavity reach the fallopian tubes. The fallopian tube receives with the help of the cilia, its extreme part, the ovum which was recently released by ovulation. In the fallopian tube, the egg will be fertilized by a single sperm. The fertilized egg (zygote) remains in the fallopian tube for the next 3-4 days where it divides into 2,4,8,16 and so on. cells as the fallopian tube guides it into the uterine cavity. This underlines the very important trophic role of the fallopian tubes which unfortunately salpingography cannot detect as it only shows us whether the fallopian tubes are open or not (hydraulic role) and not their functional integrity.

Then, on the 5th day, in the form of a blastocyst (consisting of about 60-120 cells) the embryo migrates into the uterine cavity, implants itself in the endometrium (“implantation”) and continues its development.

The reasons are mainly two: First cause is the poor genetic quality of the embryos Second cause is the strained endometrium due to the high hormones produced during an IVF

It is known that fertility decreases with age in women. This is because their eggs have more chromosomal abnormalities which are passed on to the embryos they produce.

The rates of chromosomal abnormalities in fetuses increase gradually from 1 in 385 at age 30, to 1 in 179 at age 35, 1 in 63 at age 40, and at age 45 the rates are 1 in 19. These fetuses they are not compatible with life, so either they do not implant or if they do implant they result in miscarriage. This explains the low pregnancy rates and high miscarriage rates in women over 40.

As a woman’s fertility declines over the years, so do the rates of achieving pregnancy through Assisted Reproduction. From age 31 to 34, the couple’s success rates drop by 3% for each passing year.

From the age of 35 to the age of 39, the reduction in achieving pregnancy each year amounts to 8%. From 40 to 42, 15% for each year and from 42 onwards the rates are very low.