The "natural" IVF, in fact a minimal stimulation IVF, reffers to a technique using the natural development of follicules, with the aim to "preserve" the usually hyperstimulated ones obtained in the conventional IVF.
Recent researches have shown that the conventional approach of "controlled hyperstimulation" presents some disadvantages:
- it quickly exhausts the ovarian follicles
- the ovocytes obtained are, although numerous in numberr, of poorer quality than the ones developed "naturaly" by the ovary
- the price imposed by the high doseage of IVF drugs is also important, and associates with the medical risks of treatment/
On the other hand, the natural IVF, as numerous countriees call it, has other pitfalls:
- a smaller number of ovocytes implies a poorer success rate
- although it is called "natural" there are some treatments implied, in some patients - especially if previous failures of IVF or other techniques
- the patient needs a strict monitoring protocol, as the risk of "loosing" a follicle is greater and more damaging than in the conventional IVF procedures
Therefore, natural IVF remains an option for either low chance of success, as it diminishes the associated risks, or those who are prone to have an excessive uncontrollable reaction to medication. In case of its' repeated failure, natural IVF could be followed by the use of conventional IVF. Also, natural IVF is not to be recommended in patients with repeated conventional IVF failures, those who want cryoprreservation of embryos, or a very poor semen quality.
The conventional IVF isbased on artificial ovarian stimulation, punction and aspiration of ovarian follicles (those small cysts under 20-25 mm, produced each month by the ovaries, which break during ovulation), selecting from the aspirated fluid of the female cell- the ovocyte, and putting it in close conmtact in special medium and conditions with the male cell- spermatozoa. After few hours, the latter penetrates and fertilise the ovocyte and forms the "egg" (the initial embryo, with rapidly multiplying cells). When this egg is fully mature to sustain his own development in the uterus, which takes 3 to 5 days, it is transfered in the womb and further stick to the uterine mucosa.
This method has been used in humans for over 4 decades, and its' suces rate varies according to some factors:
- age (especially that of the women) is one of the most important, the success rates halfening in patients over 38 years, and diminishing 4-5 times after 40 years.
- the cause of infertility. The best results are obtained in pacients with blocked tubes (and especially not because of inflamation, but from other factos- like tubal sterilisation), with a percentage of pregnancies approaching 40% per IVF cycle, and 70-80% per 3-4 cycles. The worst results are in patients with ovarian defficiency, best evaluated through AMH (antimullerian hormone) which values under normal give a rate of 15% success per cycle.
- male infertility can also influence the success of IVF, through the number of active spermatozoa able to fertilise the ovocyte (different sperm abnormalities, named oligo-, astheno or teratospermia), but also through other morphological changes of sperms, due for example to genetic disorders, increeased paternal age, sperm infection, etc.
- for both partners, exposure to toxic factors (smoke, alcohol, or professional toxic environment) influences the succes rate.
The practical aspects of an IVF treatment include:
1. Stimulation treatment. There are several "therapeutic protocols", which coould start even from the cycle previous to the one for IVF ("long protocol") or during the IVF cycle (day 2 and 3 of the cycle) ("short protocol"). The choice of adequate drugs, and their doseage is entirely the decision of the specialist doctor, which takes decisions based on patients details and history.
2. Monitoring- means following the ovarian response to the treatment. It's done mainly by endovaginal ultrtasound, when folllicles are being measured; sometimes, blood hormones are assessed (especially estradiol, but also progesteron, LH).
3. Inducing the ovulation- is done when there are at least 2-3 follicles of 18 mm and more in diameter, using a drug called hCG (human Chorionic Gonadotrophin) or GnRH agonist (depending on the protocol used and the response of the patient).
4. After 32 hours (sometimes before, very rarely later) an aspiration punction is performed by the vagina under ultrasound guidance, with a special needle, and usually the fluid is taken out of every follicle of over 14mm diameter. Under microscope, the aspirated fluid can have ovocytes.
5. Simultaneously, the sperms are prepared for fertilisation, by selection and astimulation in special medium. They are afterwards put into contact with the ovocyte, also in special conditions, are transfered to an incubator, which insures a temperature of 37 degrees, special air concentration, and special chemical conditions. Their development is monitorised daily until the 3rd (48-72 hours from ovarian pick-up of ovocytes) day. At this moment a thorougfh evaluation is made which allows an assessment of their quality and perspectives of development. If thhere are a minimal of 3 very good quality, there is a new step, incubating tthem for another 2 days. If there are doubts about their quality, it is preffered they are transfered to the women at this stage.
6. So, at 3 or 5 days from ovarian puncture, the best embryos are transfered in the patient's womb, with a supplementary treatment received by the women to improve the chances of the embryos "gripping" to the uterine wall. This procedure is practically painless, and it does not need even the superficial anesthesia used for the ovocyte pickup.
7. Finally, after 10 days or more from the transfer, if no menstruation occurs, the women can do a pregnancy test, either from urine or (more accurate) from the blood.
8. Confirming the pregnancy, and establising its' location (in the uterus, not in the tube) is done by ultrasound examination performed a week after the pregnancy is detected.
These steps are a general presentation, and each individual case may have a different evolution or treatment.
This is an abbreviation for IntraCytoplasmatic Sperm Injection, and it is an added prroceddure to a classical IVF, in which the contact between the ovocyte and the sperm
is "helped" by the embryologist that transport one sperm (often less motile) through the ovocyte outer membrane inside the cellular medium.
This procedure should be indicated therefore in:
- repeated failures of other methods
- small number of sperms, or low mobility (called oligo or aasthenospermia)
- small number of ovocytes obtain at pickup (under 3), but also depending on their "solidity" in morphology, so they won't be lost during ICSI.
The method improves with 5-10% the success rate of IVF procedures.