ASSISTED CONCEPTION TECHNIQUES د.نادية مضر الحلي
The birth of Louise Brown on July 25th 1978 was a landmark in the treatment of infertility.
Initially, women with tubal damage were considered for IVF-ET during spontaneous cycles. The technique is now offered for a number of other indications and generally carried out in cycles with ovarian stimulation.
In vitro fertilization and embryo transfer (IVF-ET) involves the fertilization of gametes in the laboratory and transfer of embryos to the uterus. There are a number of related techniques that are carried out to overcome barriers to enhance fertilization. The commonly used techniques are listed below.
IVF in vitro fertilization
DI donor insemination
GIFT gamete intrafallopian transfer
ZIFT zygote intrafallopian transfer
SUZI subzonal insemination
ICSI intracytoplasmic sperm injection
TESA testicular sperm aspiration
PESA percutaneous sperm aspiration
MESA micro-epididymal sperm aspiration
Of all the techniques described above, IVF and ICSI are the most commonly used techniques
Indications of IVF include:
• Tubal damage
• Unexplained infertility
• Endometriosis
• PCOS
• sperm disorder:
• non-obstructive azoospermia
• obstructive azoospermia
Typical IVF-ET cycle:
Initial consultation and tests:
Assess the cause of infertility, choose the most appropriate technique, explain the procedure, side effects, complications and success rates. An assessment of the most recent baseline FSH level, semen analysis, tubal patency test and ultrasound scans are essential before commencing treatment.
Pituitary down regulation: To prevent the risk of spontaneous LH surge necessitating_unplanned oocyte collection. Oocytes may not be collected due to rupture prior to the procedure.
So Pre-treatment with gonadotrophin-releasing hormone analogues (GnRH analogues) will help.
GnRH analogues are used either subcutaneousty or intranasally. Pituitary down-regulation is confirmed with low serum oestradiol levels or quiescent ovaries and thin endometrium as seen on ultrasound_scan. In some cases, the analogue is used prior to (short protocol) or in conjunction with (ultra-short protocol) ovarian stimulation.
Ovarian stimulation:
FSH (either recombinant or urinary) or MG injections are used daily until the leading follicles have reached 18-20 mm in diameter. This process takes normally 12-14 days.
Ovulation trigger with hCG: An injection (5000 or 10,000 IU) of hCG is administered which acts as a surrogate for LH surge. Oocyte collection is carried out 36 hours after hCG administration.
Oocyte collection:
This procedure is normally carried out under trans-vaginal ultrasound guidance as an outpatient under intravenous sedation. Once the follicular contents are aspirated, the cumulus oocyte complex is identified under microscope and incubated at 37°C in culture medium.
Semen preparation:
The main aim is to separate motile healthy spermatozoa from the seminal fluid so that they can be used for fertilization. Semen is produced, allowed to liquefy, then diluted with culture medium and centrifuged to sediment spermatozoa. Motile sperm are separated, washed and kept in culture medium for insemination.
Sperm aspiration techniques:
In men with azoospermia, sperm can be aspirated either from the testes or the epididymis and used for ICSI. Sperm aspiration is a simple technique performed under local anaesthetic on the day of the partner s egg collection.
Insemination:
In conventional IVF, prepared sperm (between 100,000 and 200,000) are added to each oocyte approximately 4-6 hours after they are collected. In cases of ICSI, sperm is injected directly into the cytoplasm of the oocyte through the zona pellucida.
Fertilization and embryo cleavage:
After 16-18 hours from insemination, the oocytes are transferred to a fresh culture medium and examined for fertilization. The presence of two pronuclei and two polar bodies indicates normal fertilization. Fertilized oocytes are re-examined to check for embryo cleavage. Embryos are graded microscopically from I to IV, with I being excellent and IV being poor.
Embryo transfer:
Embryos are normally transferred to the uterus 2-3 days after oocyte collection (i.e. 2-8 cell, stage) trans-cervically. The maximum number of embryos replaced at any one time is two, according to the Human Fertilization and Embryology Authority (HFEA).
Embryo cryopreservation
Spare embryos are cryopreserved for future use. Cryopreservation and thawing techniques, embryo quality at freezing and after thawing and clinical protocols for replacement influence the success.
Luteal support and establishment of pregnancy:
Luteal phase is supported with low dose hCG or by administration of progesterone. A urine pregnancy test or a blood test for hCG is performed 14 days after embryo transfer.
Complications of IVF treatment: Ovarian hyperstimulation syndrome & multiple pregnancy are the major concerns.