Clayo Clinic

Slovníček pojmů

Nemusíte se bát nesrozumitelných lékařských zpráv. Celým procesem léčby Vás provedeme a vše vysvětlíme.

Přesto byste se možná rádi více orientovali v odborné terminologii, proto jsme připravili abecední slovníček pojmů.

AFC (antral folicul count)

An ultrasound examination of the ovaries used to estimate the ovarian reserve in the patient according to the number of immature follicles.

AID (arteficial insemination of donor)

Intrauterine insemination using donor sperm.

AMH (antimullerian hormon)

A hormone whose value determines the ovarian reserve - "the quantity of eggs in the ovary".

Assisted hatching (AH)

The oocyte, later the embryo, is surrounded by a layer called zona pellucida. The embryo must leave this layer in order to attach to the uterus. This process is called hatching. Sometimes, the layer is too thick or stiff and thus the embryo cannot leave it. It is supposed that, in some cases, this might be the reason for infertility. This condition can be improved by an embryologist who creates a small opening in the layer so that the embryo can leave the layer easily.


The result of semen analysis where the percentage of motile sperm is below standard lower limit, i.e. below 40%.


It is a medical condition when the ejaculate contains no sperm.


Usually a 5-day old embryo, when some cells already differentiate to form a placenta (trophoblast) and some cells form a fetus (embryoblast).

Clinical pregnancy

It is a pregnancy visible in the uterus by ultrasound. Biochemical pregnancy is the phase of pregnancy when there is a positive finding of HCG hormone either in blood or urine in the pregnancy test.


A person who gives sperm, eggs or embryos.


A germ resulting from the fertilization of the egg by the sperm.


It is a new culture medium, which contains an important cytokine (GM-CSF) that creates an ideal environment for proper embryonal division and development of embryos. It is used to culture embryos within 72 hours. It is suitable for patients with recurrent reproductive failure and for patients with a history of recurrent miscarriage.


This medium is specially developed so that there is a perfect communication between the endometrium and embryo after embryotransfer. The medium is enriched in particular with hyaluronan, thereby creating a suitable environment for embryo implantation. EmbryoGlue is particularly suitable for women over 35 years.

Embryotransfer (ET)

It is transcervical placement of embryos into the uterus by a thin catheter.


A disease when endometrial cells implant outside the uterine cavity. The cause of the disease is not entirely clear. These cells may be found on the ovary and form typical endometroid cysts which are sometimes associated with infertility. If found elsewhere in the pelvis, they may cause pain or create adhesions that restrict fallopian tube patency.


A mucous membrane: it is a lining of the uterine cavity whose quality changes during a menstrual cycle. In certain phase of the cycle it can receive an embryo so that it can further develop.

ERA (endometrial receptivity array)

A test designed to show whether the endometrium can receive the embryo on the day of embryotransfer. If not, it can determine when to perform embryotransfer, i.e. whether sooner or later. It is made after repeated failure in assisted reproduction.


A small sac in the ovary filled with fluid where the egg develops. Its size in resting state is up to 8 mm. It gradually grows to a diameter of 18-24 mm when it bursts and the egg is released (see Ovulation).


Measurement of the follicle size by ultrasound. It is performed repeatedly over several days to monitor the follicular growth and to predict or evidence ovulation.

Sperm DNA fragmentation

A high standard test for testing the quality of sperm. The result is the percentage of sperm with damaged DNA in the sperm head. This test gives us more information about the quality of sperm that can be used to plan the next treatment procedure.

Genetic testing

Genetic testing is based on the interview of both partners with a clinical counsellor. Nowadays, the importance of genetic tests is often overestimated. If the woman has a regular menstrual cycle with ovulation and the man has normal results of semen analysis, the probability of finding a genetic abnormality is the same as in the general population.

GTH (gonadotrophic hormones)

Hormones that are naturally produced in the pituitary gland (an endocrine gland in the brain) and regulate ovarian function. They are also produced as medication which can "force" the ovary to grow more than one follicle. We call the process “controlled hormonal stimulation”. They are only in the form of injections.

Hormonal stimulation

The process which we start IVF treatment with. It takes place in the first half of the cycle for about 10-15 days. Using hormonal drugs, we stimulate ovarian activity so that more than one egg matures at the same time.

HyCoSy (Hysterosaplingo Contrast Sonography)

A method to examine the patency of fallopian tubes. The principle of the method is the insertion of a contrast solution into the uterus; ideally, this solution then penetrates into the fallopian tubes and abdominal cavity where it is absorbed. We monitor the process by ultrasound. This method is the most gentle of the possible examinations. The patients describe their feelings during the examination as the same as during menstruation, which then fade away. If necessary, we perform this test in a short general anaesthesia.


A minor gynaecological performance when optical technology is inserted into the uterine cavity through the vagina and cervix to examine the shape of the uterine cavity and the quality of the endometrium and to see the mouth of the fallopian tubes. The method is used to detect polyps and other pathologies. Surgical hysteroscopy is called resectoscopy when some pathological formations can be removed from the uterus by using instruments. It can be combined with a biopsy of the endometrium or HyCoSy. This all is performed in our clinic.

ICSI (intracytoplasmic sperm injection into the oocyte)

A type of fertilization when the embryologist selects a sperm according to its appearance and motility and inserts it directly into the egg.


Implantation of the embryo in the endometrium.

Implantation window

A short period of about 2 days when the endometrium is ready to receive an embryo for "implantation". It is 6-7 days after ovulation.

Induction of ovulation

If there is no oocyte maturation – ovulation, the state is called anovulation. Often, this is manifested by irregular, usually prolonged menstrual cycle. In many cases, ovulation can be induced by antiestrogenic compound of clomiphene citrate (e.g. Clostilbegyt tbl.) which is administered in the first half of the cycle. The use of progestogens (progesterone) themselves in the second half of the menstrual cycle induces menstruation, but not ovulation, and thus it does not make sense to use them in this way. About 80% of women react well on clomiphene citrate and similar substances, but only about 60% of them become pregnant. It is reported that if a woman does not become pregnant after three or six cycles at maximum, there is no sense in further use of clomiphene citrate.

Another group of drugs that induce - stimulate ovulation are gonatrophic hormones. They are in the form of subcutaneous injections which are applied in the first half of the cycle and such stimulation must be monitored by ultrasound - folliculometry. Since the treatment with gonadotrophic hormones is more expensive, we try to maximize the chance, and therefore we always combine stimulation of ovulation through GTH with intrauterine insemination.

IUI (intrauterine insemination)

Cleaned sperms are inserted by a thin catheter directly into the uterine cavity.

IVF (in vitro fertilization)

Fertilization which takes place outside the body.

IVF cyklus s minimální stimulací

IVF cyklus, kdy podáváme nižší množství stimulačních léků než je obvyklé. Pak očekáváme růst méně folikulů, někdy jen jednoho.

FET (Frozenembryotransfer)

Today we freeze embryos only by using the method called vitrification. This method is more expensive than previously performed slow freezing, but it ensures a greater likelihood of good embryo survival after thawing.

Embryos can be freezed (cryopreserved) theoretically for unlimited period of time. The advantage of FET is its simplicity which eliminates the ovarian stimulation and egg retrieval, i.e. injections and general anaesthesia. Although the treatment cycles with frozen embryos are not covered by public health insurance, it is generally less costly than IVF+ET treatment. If the couple has embryos frozen, it has a chance to conceive using FET and does not need to undergo the next intensive IVF process.

A pregnancy success rate is slightly lower than in the “fresh cycle” (IVF + ET), but today the total number of children born after FET is high. FET is planned either in the natural (native) cycle, or with hormonal support, i.e. hormone replacement therapy (HRT). In natural cycle, FET can be planned only if the woman ovulates in her cycle. It is therefore necessary to monitor ovulation by ultrasound, i.e. perform the folliculometry, to determine the day of ovulation. This requires about 2-4 ultrasound examinations. During ovulation, not only that the follicle releases an egg to be fertilized, which in this case is not needed, but this follicle is hormonally active and prepares the endometrium for implantation of the embryotransferred by us. The embryotransfer is performed 2-5 days after ovulation according to the age of the embryo. In FET with HRT support the endometrium is being prepared by using estrogens and progestogens. It most often consists only in taking tablets and vaginal capsules. A fewer ultrasound examinations are needed (1-2). Both medications are used until a positive pregnancy test and when pregnancy occurs, both medications need to be used for FET with HRT support until the 12th week of pregnancy as there is no corpus luteum!

Freezing (cryopreservation)

Sperms, eggs and embryos can be freezed in liquid nitrogen theoretically for unlimited period of time. In this state, no processes are ongoing in the cells, everything stops and the activity renews after thawing.


A minimally invasive surgical method of abdominal surgery when operations on the organs of the abdominal cavity or small pelvis are performed while using long thin instruments under the control of cameras. It is performed under general anaesthesia and requires brief hospitalization.

Low responder

A patient who is less responsive to hormonal stimulation in IVF process. These are usually patients with low ovarian reserve.

Menstrual cycle

The cycle begins on the first day of bleeding and ends on the first day of further bleeding. It is therefore calculated from the beginning to the beginning of menstruation. If bleeding comes by 10 o'clock in the morning (not just blood spotting), we count it as the first day of the cycle. However, if bleeding occurs after 10 o'clock in the morning, it is a zero day and the first day of the cycle is the following day.

MESA (Microsurgical Epididymal Sperm Aspiration)

It is used in patients with obstructive azoospermia. It is a microsurgical aspiration of sperm from the epididymis.


A frequently occurring benign "tumor" in the uterus. It occurs in the muscle of the uterus (myometrium) where it creates defined "balls" that distort the uterus. According to whether they occur closer to the uterine cavity, in the middle of the myometrium or on the surface of the uterus, they are divided into submucosal, intramural and subserosal. They might be associated with the inability to conceive or recurrent miscarriage, but there might not be the connection. It depends on their size and location in the uterus. Sometimes they are removed, sometimes they are left there. There is already conservative treatment, too.

Natural IVF cycle

The IVF cycle where no hormonal drugs are administered to stimulate egg production.


Normal values of sperm analysis in all parameters.

OHSS (ovarian hyperstimulation syndrome)

Excessive ovarian response to hormonal stimulation in IVF process. It is a set of symptoms, such as enlarged ovaries, lower abdominal pressure or pain, nausea, vomiting, reduced urination, etc.


Abnormal result of sperm analysis when the sperm concentration in the ejaculate is less than the standard lower limit, i.e. 15 mil./ml.


Egg. It is the biggest cell in the human body with a diameter of 0.1 mm.

Ovarian reserve

In simple terms, it is a "number of eggs in the ovary". Women have the highest values of ovarian reserve after puberty and these values decrease with growing age. The value of ovarian reserve as well as the rate of its decline is very individual. The ovarian reserve is estimated from the level of FSH (follicle-stimulating hormone) or rather level of AMH (anti-Müllerian hormone), but also by ultrasound ovarian examination – AFC (antral follicle count).


A female reproductive organ in a lesser pelvis which produces oocytes and is hormonally active.


The burst of a growing follicle and the release of an egg from a follicle in the ovary.

PGD/PGS (preimplantation genetic diagnosis/preimplantation genetic screening)

A method in the IVF process where an embryo is genetically tested whether it is healthy. The number of some or all chromosomes can be tested in the embryo, i.e. whether any chromosomes are missing or present abundantly, to exclude the Down’s syndrome or testing for hereditary diseases where there is a real risk of inheriting the disease.

PICSI (preselected intracytoplasmic sperm injection)

It is a modified ICSI method where based on the functional assay a sperm is selected and then injected into the egg. The method is suitable for couples with recurrent poor quality of embryos or repeated failure. It can be used as soon as the first IVF cycle when the couple wants to maximize their treatment in that cycle. The PICSI method can not be used if a semen analysis shows significantly pathological results, with low sperm count or completely immotile sperm.

Plodné dny

Období v menstruačním cyklu ženy, kdy lze otěhotnět. Je to v období ovulace, s maximálním rozpětím až 7 dní před ovulací a 3 dny po ovulaci. Pokud má žena cyklus 28 dní, pak je to 14. den jejího cyklu. Pokud má žena cyklus kratší, nastává ovulace dříve – např. při cyklu 25 dní jde o 11. den cyklu. Pokud má žena cyklus delší, nastává ovulace později – např. při cyklu 35 dní nastává ovulace až 21. den.


Also a „villus” or a „mucosal pouch”. In gynaecology, we can find endometrial polyps in the uterine cavity or cervix. If a woman who wants to conceive has a uterine polyp, it must be removed. Sometimes such a polyp acts like an IUD and thus prevents pregnancy. Histological examination of the polyp can exclude a possible malignant polyp which is, however, rare in women of reproductive age.

Prodloužená kultivace

Kultivace embryí v laboratorních podmínkách déle než 48 hodin, maximálně však 144 hodin. Prodloužená kultivace slouží k výběru nejvhodnějších embryí pro embryotransfer. Pokud kultivujeme embrya déle než 48 hodin, můžeme tak lépe vyhodnotit kvalitu jejich vývoje a jejich životaschopnost.

Oocyte puncture

Transvaginal aspiration of follicular fluid containing the eggs from the ovary to obtain the eggs for IVF process to fertilize them in the laboratory. It is performed in short general anaesthesia through a thin needle.

Reproductive period of a woman

A time period when the woman can become pregnant. This reproductive period may vary for each woman within several years. The female’s ability to conceive ends many years before the last menstrual bleeding in life. The female’s inability to conceive after the age of 40 is not seen as a disease, but a physiological process of reproductive aging.


A dilated fallopian tube with inflammation where both tubular ends stick together and the tube is filled with fluid. Such filled fallopian tube can be seen by ultrasound examination. Sometimes, we distinguish hydrosalphinx where the fallopian tube is filled for a long time, its walls are thinned and the inflammation is healed, and pyosalphinx which is an ongoing acute inflammation and the fallopian tube contains pus. In its acute phase, it is treated with antibiotics. Such fallopian tube is often irreversibly damaged and sometimes it is better to remove it.

Social freezing

Freezing of oocytes at the age when the woman is young and still has quality oocytes. For well known reasons, many women now decide to have a baby in their 40s. It is generally known that the ability to conceive decreases with age. In order to give the older woman a chance to have her biological child, the eggs freezed in her “reproductive youth” can be thawed and used in the IVF+ET programme. It is necessary to freeze eggs by the age of 35 for this method to be successful.

Semen analysis (spermiogram)

Examination of the ejaculate (sperm), based on which male fertility is assessed. Several days of sexual abstinence are recommended before undergoing this examination.


The abnormal test result of semen analysis when the ejaculate contains an increased percentage of sperms with abnormal shape. The standard is very liberal. We speak about teratospermia if the percentage is higher than 96%.

TESE (Testicular Sperm Extraction)

A surgery that is performed under general anaesthesia in patients with azoospermia. The purpose is to obtain sperms directly from the male gonad. The testicle cover is cut open to obtain testicular seminiferous tubules and find sperms under the microscope. The sperm can be freezed or used directly for fertilization using the ICSI method. This surgery can be synchronized with the stimulation of the woman when TESE is performed on the day of the egg retrieval (OPU). At our clinic we perform both of these options. The TESE is performed on an outpatient basis and is not covered by public health insurance.

Time-lapse embryo monitoring system

A method allowing continuous monitoring of the embryo development under unchanging environmental conditions. Using this method, we have a complete overview of the development of each individual embryo. Based on the dynamics of differentiation and other parameters, an embryologist has the option to choose the best quality embryos for embryotransfer and decide which embryos are suitable for freezing. This method must be combined with ICSI/PICSI methods.


Fast freezing used for freezing the embryos and oocytes. This method is more expensive than previous slow freezing, but ensures better survival of embryos or oocytes after thawing. Embryos/oocytes can be freezed in liquid nitrogen theoretically for an unlimited period of time.

Corpus luteum

A structure on the ovary formed by remaining cells of the follicle after ovulation. It is hormonally active and it produces oestrogens and mainly progesterone preparing the endometrium to accept the embryo and ensuring its successful development until this function is taken over by the placenta in about the 12th week of pregnancy.

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