IVF-treatment – this is how it works
The treatment was first introduced in Sweden in the beginning of the 80's and in 1982, only four years after the first IVF delivery in the world, the first "IVF-baby" in Sweden was born.
In the beginning IVF was used in the situation of tubal dysfunction or tubal damage. It was soon found that IVF could be successfully applied in the situation where the sperm sample was found to have a low fertilising capacity.
Fertilisation in glass
In vitro fertilisation literally means "fertilisation in glass". This "glass" can either be a test tube or a Petri dish. The oocytes (eggs) are retrieved from the ovaries of the female and put together with her partner's sperm in the test tube or the Petri dish to facilitate fertilisation.When fertilisation has occurred and cleavage is starting the embryo is replaced in the womb. In vitro fertilisation you are the biological parents of the pregnancy even if the fertilisation takes place outside the body.
Spontaneous ovulation is regulated by a series of signals to the ovaries, mediated by hormones from the pituitary gland in the brain to the ovaries. In most women, one oocyte (egg) matures in the middle of each menstrual cycle and is released from the ovary. This oocyte is captured by the fallopian tube and smoothly transported down the tube towards the uterus.
During this transport fertilisation takes place by those sperms that have been able to make the journey up through the cervical canal to the fallopian tube. The early cleavage of the oocyte, leading to an embryo, takes place during the transport in the fallopian tube down to the womb. Approximately on day 4-6 after ovulation the cleaved oocyte (embryo) does attach to the endometrium (the lining of the womb). When this attachment or nidation has taken place the woman is pregnant.
Preparatory investigation
When you are about to enter an IVF treatment, you have been through extensive investigations and do know the reasons to your problem. These reasons are equally often found in the female as in the male. In most cases there are several contributing factors to the subfertility and in some cases the subfertile situation cannot be explained, e.g. unexplained subfertility.
As in all biological processes no exact age limit could be estimated. It is of course necessary, though, that the female has not entered the menopause. In standard IVF the sperm count, or the motility of the sperm, can be slightly depressed, but still within well defined limits. One must be aware of that the chance to become pregnant through IVF does decrease with advancing age in the same way as it does in spontaneous conception.
The treatment itself
The stimulation of the follicular and oocyte maturation will either start with a suppression of the spontaneous hormone production from the pituitary. When this spontaneous production has reached a very low level the female will have supplementary hormonal stimulation (FSH).
The suppression of the spontaneous hormone production will prevent spontaneous ovulation.
This could also be achieved by administrating a so-called antagonist after approximately one week of FSH administration. The maturation of the follicles and oocytes are monitored with hormonal analysis and ultrasound examinations.
When the follicles have reached a certain size and this corresponds to the hormonal levels, it is time to retrieve the oocytes from the follicles. This does normally occur twelve to fifteen days after the hormonal stimulation has started. The oocyte recovery is performed by a transvaginal ultrasound guided puncture of the follicles.
On the ultrasound screen the follicles can be visualized, approximately 20 mm in diameter. The oocyte retrieval will normally take about 20 minutes. During this procedure analgesia is applied but no full anaesthesia. The follicular fluid and the oocytes are collected in a test-tube. This fluid is examined in the laboratory through the microscope and the oocytes, approximately 1/10 of a mm in size, are moved to a Petri dish containing culture medium. In the morning of the day of the oocyte recovery the husband will produce a sperm sample in the clinic. The sperms are counted and prepared and after a couple of hours put in the same Petri dish as the oocytes. The mixture of oocytes and sperms is left in an incubator where the environment is kept at its optimum concerning temperature, pH and osmolality to facilitate the fertilization.
After 24 hours and 48 hours the oocytes, now developing to embryos, are examined through the microscope. The quality of the embryos is examined very thoroughly. Only first-grade embryos are considered for embryo transfer. This procedure does normally take place 48, in some cases 72 hours, after oocyte recovery. The embryo transfer, which is the name of the replacement of the fertilized oocytes, takes 5-10 minutes and could be compared to an ordinary gynaecological examination.
Most women will prefer to take it a little bit easy during the coming couple of days. It should be emphasized, though, that no actions in ordinary life would affect the chance of the pregnancy to establish. Most importantly, the embryos cannot fall out. If the treatment should not be successful a subsequent treatment could be started again after 1-2 months.
It is obvious that the chance of a pregnancy do increase if more than one fertilised oocyte (embryo) is replaced in the woman's womb. With improved results after IVF, a maximum of two embryos are replaced. This is to avoid multiple pregnancies.