By using the term In-Vitro Fertilization we signify a wide range of techniques that their purpose is to help infertile couples to have a child. Since the birth of Louise Brown in 1978, the first birth of an IVF assisted child in Bourn Hall, England, thousands of couples were successful. IVF may solve today's problems related to both female (e.g. fallopian tubes obstruction) and male (e.g. oliogospermia) infertility. Success rates depend on many factors such as the age of the woman and the cause of infertility. Normally, the cumulative success rate can reach sixty to sixty five percent (60-65%) after three (3) to four (4) IVF cycles.
During the treatment, stimulation drugs are administered to increase the number of the eggs produced by the female during her normal menstrual cycle. This production is then monitored by ultrasound scans and blood tests at regular intervals, usually every two (2) or three (3) days and medication doses are carefully adapted to be patient-specific. Vaginal ultrasound scans monitor the response of the growing follicles that host the eggs in the ovary. Once a follicle is over eighteen millimeters (18mm) in size, the egg is considered mature and ready for retrieval. At the same time, it is appropriate to measure the endometrial lining thickness increase. The endometrium covers the endometrial cavity, which will later host the embryos. Blood oestradiol tests are performed since the oestradiol levels produced from the follicles are an index of the eggs maturity. Beta-hCG is administered to trigger the final maturing of the eggs. In general, an adequate number of follicles with a mean diameter of at least 18mm, a good endometrial lining thickness as well as an appropriate oestradiol level must be present before hCG is administered. Eggs retrieval is scheduled thirty four to thirty eight hours after hCG injection.
Egg retrieval is 15-minute procedure that is performed under mild sedation (light anesthesia). The follicular fluid from the ovaries is retrieved from the patient using a transvaginal technique involving an ultrasound-guided needle piercing the vaginal wall to reach the ovaries. Through this needle, follicular fluid can be aspired and handed to the embryologist to identify ova.
After egg retrieval, the mature eggs are placed in a culture medium containing processed sperm to achieve fertilization. The eggs are then incubated overnight. The next morning, a fertilization check takes place and the evolution of the whole process is continuously monitored.
Embryo transfer is a simple procedure that does not require sedation. It typically occurs two (2) to three (3) days after eggs retrieval. In some cases, blastocyst transfer, i.e. transfer of embryos at the blastocyst stage, six (6) to seven (7) days after eggs retrieval, is preferred. Embryos are loaded into a slim plastic catheter and the embryologist threads the catheter through the cervix and into the uterus where he deposits the embryos. The number of embryos transferred is decided jointly with the couple. If a large number of embryos are available, some of them can be cryopreserved for a future attempt.
A pregnancy test is usually performed twelve (12) days after embryo transfer. Blood is typically drawn and human Chorionic Gonadotropin levels are measured. In case the test is positive, the first ultrasound scan is performed two weeks later. This scan reveals the embryonic sac(s) of the fetus in the womb. If the test is negative the medication administration is discontinued and the effort is then put to the investigation of the potential causes of failure and making further decisions.
INFERTILITY TREATMENT - LABORATORY TECHNIQUES
Assisted Follicular rupture
This treatment is indicated for women with follicular rupture disorders, i.e. women with irregular menstrual cycles or Amenorrhea. The follicular disorder is treated by the administration of drugs either orally (clomiphene) or via injections (FSH). Ultrasound check is performed in order to observe the follicles development and when one of these becomes larger than 17 mm, a timed intercourse between husbands should take place. The rate of success is six to ten percent (6-10%) per treatment cycle. The chance of a multiple pregnancy is in the range of ten to twenty percent (10-20%).
Assisted Follicular rupture and Intrauterine Insemination (IUI)
- It is indicated for women for which the latter treatment was unsuccessful as well as in cases of inexplicable infertility, hostile cervical conditions and mild problems associated with the male factor (mild disorders of the sperm cell diagram).
- Medication and progress monitoring are identical to the ones in the latter treatment. The only difference is that instead of sexual intercourse, the husband gives sperm to the laboratory. The sperm is properly prepared in the lab with special techniques. The processed sperm is then injected into the uterine cavity. The IUI pregnancy rate is eight to eighteen percent (8-18%). The multiple pregnancy rate is in the range of ten to twenty five percent (10-25%).
IN-VITRO FERTILIZATION - TECHNIQUES
A. Conventional In-Vitro Fertilization (IVF)
In the conventional IVF procedure, the eggs are placed in contact with the sperm in culture medium and they are incubated until fertilization is observed. Only one sperm will manage to penetrate the egg and start the process of fetus development.
B. Microfertilization (Intra-Cytoplasmic Sperm Injection)
The ICSI procedure entails the injection of a single sperm directly into an egg (cytoplasm). This procedure is most commonly used to overcome male infertility problems (disorders of the sperm cell diagram) or azoospermia (in this case the sperm is directly collected from the testicular tissue). It is also indicated in cases of egg fertilization failure through conventional IVF at an earlier attempt.
C. Assisted hatching
Assisted hatching is a laboratory technique which helps conventional IVF or ICSI-created embryos to hatch prior to their transfer in the uterus. Assisted hatching is a procedure in which the outer layer of the embryo is thinned in order to facilitate implantation. It is particularly recommended in cases where the embryologist concludes that the outer layer is hard or thick. In general, this technique is preferred for older women and patients with repeated implantation failures in IVF cycles.
D. Blastocyst culture
The term blastocyst describes a certain stage of embryo development after five (5) to six (6) days of culture. In the conventional IVF or ICSI process, embryos are typically cultured for two (2) to three (3) days before being transferred into the uterus. By extending the culture to five (5) or six (6) days (blastocyst culture), the embryologist is able to select more advanced embryos with better potential for implantation at the time of the transfer. The disadvantage is that there is a possibility that none of the embryos may survive to that stage.
E. Embryos and testicular tissue cryopreservation
Cryopreservation is performed in special liquid nitrogen tubes at a temperature of -196oC. Cryopreservation of embryos is preferred in the case that excess fertilized embryos are available or the prevailing conditions for their implantation in the uterus are not favorable. Frozen embryos can be preserved and transferred to the uterus at a later time. Cryopreservation can also be applied for sperm and testicular tissue. Cryopreservation of ovarian tissue and eggs is still on a research stage.
F. Pre-Implantation Genetic Diagnosis
Pre-Implantation Genetic Diagnosis refers to procedures performed on the genetic material of the embryos prior to the selection and transfer of healthy embryos that were IVF assisted or otherwise conceived. At present PGD in Greece is limited to cystic fibrosis and beta-thalassemia. A more detailed description of this technique is available in the special section.
G. Testicular Sperm Extraction
TESE is recommended in the case of impaired sperm production or azospermia. If viable spermatozoa are recovered with TESE they can subsequently be used for microfertilization (ICSI).
PRE-IMPLANTATION GENETIC DIAGNOSIS (PGD)
The term Pre-Implantation Genetic Diagnosis (PGD) describes the procedure of tracking genetic diseases in order to select and transfer healthy embryos that were IVF assisted. The purpose of PGD is to allow couples to screen their embryos for inherited genetic diseases and disorders.
The discussed technique is relatively old. The first children that had undergone biopsy in the embryo stage in order to determine their sex and avoid thus the transmission of a sex-related genetic disease, were born in Hammersmith in 1989. Since those days, scientists and clinical doctors have extended the number of diseases that can be detected and therefore more than two hundred (200) children were born healthy and free of a genetic disease.
Our team, in cooperation with the Pediatrics Department of the Agia Sophia Children’s Hospital, offers an innovative program of pre-implantation detection of Cystic Fibrosis and beta-thalassemia.
The first child subjected to PGD in the embryo stage for beta-thalassemia in Greece was born in 1998.
- It is recommended in cases that earlier treatments were unsuccessful or for women with obstructed fallopian tubes or in the case of serious problems associated with the male partner (serious sperm cell diagram disorders).
- The IVF success rate depends on the woman’s age, ovaries ability to produce eggs, sperm quality, infertility cause and duration, precedent pregnancies, and last but not least, the effect of toxic factors (e.g., smoking, alcohol).
- Success rate is a function of all the aforementioned factors and it normally can reach sixty to sixty five percent (60-65%) after three (3) to four (4) IVF cycles.
- The chance for a multiple pregnancy is up to twenty five percent (25%).