y = y 0 + R sina,

D i+1 [with y i+1 = y i-1] = 2x 2 i+1 +2y 2 i+1 +4x i+1 -2y i+1 +3-2R 2 = 2(x i+1) 2 +2(y i-1) 2 +4(x i+1)-2(y i-1)+3-2R 2 = D i +4(x i-y i)+10.

Now that we have obtained the recurrent expression for D i+1 via D i, it remains to obtain D 1 (the control value at the starting point.) It cannot be obtained recurrently, because the previous value is not defined, but it can easily be found directly

x 1 = 0, y 1 = R Yu D 1 1 = (0+1) 2 +( R-1) 2 -R 2 = 2-2R,

D 1 2 = (0+1) 2 + R 2 -R 2 = 1

D 1 \u003d D 1 1 + D 1 2 \u003d 3-2 R.

Thus, the circle construction algorithm implemented in bres_circle is based on sequential selection of points; depending on the sign of the control value D i the next point is selected and the control value itself is changed as necessary. The process starts at point (0, r), and the first point placed by the sim procedure has coordinates ( xc, yc+r). At x = y the process ends.

Straight line output algorithm

Because a cathode ray tube (CRT) raster display screen can be viewed as a matrix of discrete elements (pixels), each of which can be backlit, it is not possible to directly draw a line from one point to another. The process of determining the pixels that best approximate a given segment is called rasterization. When combined with the process of line-by-line rendering of an image, it is known as raster scan conversion. For horizontal, vertical and inclined at an angle of 45°. segments, the choice of raster elements is obvious. In any other orientation, it is more difficult to select the desired pixels, as shown in Fig. 1.

Fig.1.1. Raster decomposition of line segments.

The general requirements for algorithms for drawing segments are as follows: The segments must look straight, begin and end at given points, the brightness along the segment must be constant and independent of length and slope, and must be drawn quickly.

Constant brightness along the entire segment is achieved only when drawing horizontal, vertical and inclined lines at an angle of 45°. For all other orientations, rasterization will result in brightness unevenness, as shown in Fig. 1.

Most line drawing algorithms use a stepwise algorithm to simplify calculations. Here is an example of such an algorithm:

Simple step-by-step algorithm

position = start

step = increment

1. if position - end< точность then 4

if position > end then 2

if position< конец then 3

2. position = position - step

3. position = position + step

4. finish

Bresenham's algorithm.

Although the Bresenham algorithm was originally developed for digital plotters, it is equally suitable for use with CRT raster devices. The algorithm selects optimal raster coordinates to represent the segment. During operation, one of the coordinates - either x or y (depending on the slope) - changes by one. Changing another coordinate (to 0 or 1) depends on the distance between the actual position of the segment and the nearest grid coordinates. We will call this distance an error.

The algorithm is constructed in such a way that only the sign of this error needs to be checked. In Fig. 3.1 this is illustrated for the segment in the first octant, i.e. for a segment with a slope ranging from 0 to 1. From the figure you can see that if the slope of the segment from the point (0,0) is greater than 1/2, then the intersection with the line x = 1 will be located closer to the line y = 1 than to the straight line y = 0. Consequently, the raster point (1,1) better approximates the course of the segment than the point (1,0). If the slope is less than 1/2, then the opposite is true. for a slope of 1/2 there is no preferred choice. In this case, the algorithm selects the point (1,1).

Fig.3.2. Graph of the error in Bresenham's algorithm.

Since it is desirable to check only the sign of the error, it is initially set to -1/2. Thus, if the angular coefficient of the segment is greater than or equal to 1/2, then the error value at the next raster point with coordinates (1,0) can be calculated as

e= e + m

Where m- angular coefficient. In our case, with an initial error value of -1/2

e = 1/2 + 3/8 = -1/8

Because e negative, the segment will pass below the middle of the pixel. Therefore, a pixel at the same horizontal level better approximates the position of the segment, so at does not increase. We calculate the error in the same way

e= -1/8 + 3/8 = 1/4

at the next raster point (2,0). Now e positive, it means the segment will pass above the midpoint. Raster element (2,1) with the next largest coordinate at better approximates the position of the segment. Hence at increases by 1. Before considering the next pixel, it is necessary to correct the error by subtracting 1 from it. We have

e = 1/4 - 1 = -3/4

Note that the intersection of a vertical line x= 2 with a given segment lies 1/4 below the line at= 1. If we move the segment 1/2 down, we get exactly the value -3/4. Continuing the calculations for the next pixel gives

e = -3/4 + 3/8 = -3/8

Because e is negative, then y does not increase. From all that has been said, it follows that the error is the interval cut off along the axis at the considered segment in each raster element (relative to -1/2).

Let us present Bresenham's algorithm for the first octant, i.e. for case 0 =< y =< x.

Bresenham's algorithm for decomposing a segment into a raster for the first octant

Integer- conversion function to integer

x, y, x, y - integers

e - real

initialization of variables

Half-pixel corrected initialization

e = y/x - 1/2

start of the main cycle

for i = 1 to x

while (e => 0)

e = e + y/x

The block diagram of the algorithm is shown in Fig. 3.3. An example is given below.

Rice. 3.3. Block diagram of Bresenham's algorithm.

Example 3.1. Bresenham's algorithm.

Consider a segment drawn from point (0,0) to point (5,5). Decomposing a segment into a raster using the Bresenham algorithm leads to the following result:

initial settings

e = 1 - 1/2 = 1/2

The result is shown in Fig. 3.4 and coincides with what was expected. Note that the raster point with coordinates (5,5) is not activated. This point can be activated by changing the for-next loop to 0 to x. The activation of the point (0,0) can be eliminated by placing a Plot statement immediately before the next i line.

Rice. 3.4. The result of the Bresenham algorithm in the first octant.

IN next section the general Bresenham algorithm is described.

4. General Bresenham algorithm.

In order for the implementation of the Bresenham algorithm to be complete, it is necessary to process segments in all octants. The modification is easy to do, taking into account in the algorithm the number of the quadrant in which the segment lies and its angular coefficient. When the absolute value of the slope is greater than 1, at is constantly changing by one, and the Bresenham error criterion is used to decide whether to change the value x. The choice of a constantly changing (by +1 or -1) coordinate depends on the quadrant (Fig. 4.1.). The general algorithm can be formulated as follows:

Generalized integer Bresenham quadrant algorithm

it is assumed that the ends of the segment (x1,y1) and (x2,y2) do not coincide

all variables are considered integers

Sign- a function that returns -1, 0, 1 for a negative, zero and positive argument, respectively

initialization of variables

x = abs(x2 - x1)

y = abs(y2 - y1)

s1 = Sign(x2 - x1)

s2 = Sign(y2 - y1)

exchange of values ​​x and y depending on the slope of the segment

ify< x then

endif

initialization  adjusted to half pixel

 = 2*y - x

main loop

for i = 1 tox

Plot(x,y)

while( =>0)

if Exchange = 1 then

 =  - 2*x

end while

if Exchange = 1 then

 =  + 2*y

Fig.4.1. Analysis of cases for the generalized Bresenham algorithm.

Example 4.1. generalized Bresenham algorithm.

For illustration, consider a segment from point (0,0) to point (-8, -4).

initial settings

results of the step-by-step cycle

Fig.4.2. The result of the generalized Bresenham algorithm in the third quadrant.

Figure 4.2 shows the result. Comparison with Fig. 2.2 shows that the results of the two algorithms are different.

The next section discusses Bresenham's algorithm for generating a circle.

Bresenham's algorithm for generating a circle.

Not only linear, but also other, more complex functions need to be decomposed into a raster. A significant number of works were devoted to the decomposition of conic sections, i.e., circles, ellipses, parabolas, hyperbolas. Most attention, of course, is given to the circle. One of the most efficient and easy to understand circle generation algorithms is due to Bresenham. First, note that you only need to generate one-eighth of the circle. Its remaining parts can be obtained by successive reflections, as shown in Fig. 5.1. If the first octant is generated (from 0 to 45° counterclockwise), then the second octant can be obtained by mirroring with respect to the straight line y = x, which together gives the first quadrant. The first quadrant is reflected relative to the line x = 0 to obtain the corresponding part of the circle in the second quadrant. The upper semicircle is reflected relative to the straight line y = 0 to complete the construction. In Fig. 5.1 shows two-dimensional matrices of the corresponding transformations.

Rice. 5.1. Generating a full circle from an arc in the first octant.

To derive the algorithm, consider the first quarter of a circle with its center at the origin. Note that if the algorithm starts at the point x = 0, y = R, then when generating a circle clockwise in the first quadrant at is a monotonically decreasing function of the arguments (Fig. 5.2). Likewise, if the starting point is y = 0, X == R, then when generating a circle counterclockwise X will be a monotonically decreasing function of the argument u. In our case, clockwise generation is selected, starting at the point X = 0, y = R. It is assumed that the center of the circle and the starting point are exactly at the raster points.

For anyone given point on a circle, when generating clockwise, there are only three possibilities to select the next pixel that best approximates the circle: horizontally to the right, diagonally down and to the right, vertically down. In Fig. 5.3 these directions are designated m H , m D , m V respectively . The algorithm selects a pixel for which the square of the distance between one of these pixels and the circle is minimal, i.e., the minimum of

m H = |(x i + 1) 2 + (y i) 2 -R 2 |

m D = |(x i + 1) 2 + (y i -1) 2 -R 2 |

m V = |(x i) 2 + (y i -1) 2 -R 2 |

The calculations can be simplified if we note that in the vicinity of the point (xi,yi,) only five types of intersections of the circle and the raster grid are possible, shown in Fig. 5.4.

Rice. 5.4. The intersection of a circle and a raster grid.

The difference between the squared distances from the center of the circle to the diagonal pixel (x i, + 1, y i - 1) and from the center to a point on the circle R 2 is equal to

 i = (x i + 1) 2 + (y i -1) 2 -R 2

As in the Bresenham algorithm for a segment, it is advisable to use only the sign of the error, and not its magnitude, to select the corresponding pixel.

When  i< 0 диагональная точка (x i , + 1, у i - 1) is located inside a real circle, i.e. these are cases 1 or 2 in Fig. 5.4. It is clear that in this situation one should choose either pixel (x i, + 1, at i) , i.e. m H, or pixel (x i, + 1, at i - 1), i.e. m D . To do this, first consider case 1 and check the difference in the squared distances from the circle to the pixels in the horizontal and diagonal directions:

 = |(x i + 1) 2 + (y i) 2 -R 2 | - |(x i + 1) 2 + (y i -1) 2 -R 2 |

At < 0 расстояние от окружности до диагонального пиксела больше, чем до горизонтального. On the contrary, if  > 0, the distance to the horizontal pixel is greater. Thus,

at <= 0 выбираем m H в (x i , + 1, у i - 1)

for  > 0, select m D in (x i, + 1, y i - 1)

At  = 0, when the distance from the circle to both pixels is the same, we select the horizontal step.

The number of calculations required to estimate the value of  can be reduced by noting that in case 1

(x i + 1) 2 + (y i) 2 -R 2 >= 0

since diagonal pixel (x i, + 1, at i - 1) always lies inside the circle, and horizontal (x i, + 1, at i ) - outside of it. Thus,  can be calculated using the formula

= (x i + 1) 2 + (y i) 2 -R 2 + (x i + 1) 2 + (y i -1) 2 -R 2

Complementing the full square of the term (y i) 2 using addition and subtraction - 2y i + 1 gives

= 2[(x i + 1) 2 + (y i -1) 2 -R 2 ] + 2y i - 1

By definition,  i and its substitution are in square brackets

 = 2( i + y i ) - 1

greatly simplifies the expression.

Consider case 2 in Fig. 5.4 and note that the horizontal pixel (x i, + 1, y i) must be chosen here since y is a monotonically decreasing function. Checking the components  shows that

(x i + 1) 2 + (y i) 2 -R 2< 0

(x i + 1) 2 + (y i -1) 2 -R 2< 0

since in case 2 the horizontal (x i, + 1, y i) and diagonal (x i, + 1, y i -1) pixels lie inside the circle. Therefore, < 0, и при использовании того же самого критерия, что и в случае 1, выбирается пиксел (x i , + 1, у i).

If  i > 0, then the diagonal point (x i, + 1, y i -1) is outside the circle, i.e. these are cases 3 and 4 in Fig. 5.4. In this situation, it is clear that either the pixel (x i, + 1, y i -1) or (x i, y i -1) must be selected . Similar to the analysis of the previous case, the selection criterion can be obtained by first considering case 3 and checking the difference between the squared distances from the circle to the diagonal m D and vertical m V pixels,

i.e.  " = |(x i + 1) 2 + (y i -1) 2 -R 2 | - |(x i) 2 + (y i -1) 2 -R 2 |

When " < 0, the distance from the circle to the vertical pixel (x i, y i -1) is greater and you should select a diagonal step to the pixel (x i, + 1, y i -1). On the contrary, in the case " > 0, the distance from the circle to the diagonal pixel is greater and you should choose a vertical movement to the pixel (x i, y i -1). Thus,

at  " <= 0 select m D in (x i +1, y i -1)

at  " > 0 select m V in (x i, y i -1)

Here in case  " = 0, i.e. when the distances are equal, the diagonal step is selected.

Checking components  " shows that

(x i) 2 + (y i -1) 2 -R 2 >= 0

(x i + 1) 2 + (y i -1) 2 -R 2< 0

because for case 3, the diagonal pixel (x i +1, y i -1) is outside the circle, while the vertical pixel (x i, y i -1) is inside it. This allows us to write  " as

" = (x i +1) 2 + (y i -1) 2 -R 2 + (x i) 2 + (y i -1) 2 -R 2

Completing the perfect square of the term (x i) 2 by adding and subtracting 2x i + 1 gives

" = 2[(x i +1) 2 + (y i -1) 2 -R 2 ] - 2x i - 1

Using the definition  i brings the expression to the form

" = 2( i - x i )- 1

Now, considering case 4, we again note that we should choose the vertical pixel (x i, y i -1), since y is a monotonically decreasing function as it increases X.

Checking components  " for case 4 shows that

(x i +1) 2 + (y i -1) 2 -R 2 > 0

(x i) 2 + (y i -1) 2 -R 2 > 0

since both pixels are outside the circle. Therefore,  " > 0 and when using the criterion developed for case 3, the correct choice of m V occurs .

It remains to check only case 5 in Fig. 5.4, ​​which occurs when the diagonal pixel (x i, y i -1) lies on the circle, i.e.  i = 0. Checking the components  shows that

(x i +1) 2 + (y i) 2 -R 2 > 0

Therefore,  > 0 and the diagonal pixel (x i +1, y i -1) is selected. Similarly, we evaluate the components  " :

(x i +1) 2 + (y i -1) 2 -R 2 = 0

(x i +1) 2 + (y i -1) 2 -R 2< 0

and  " < 0, что является условием выбора правильного диагонального шага к (x i +1 , у i -1) . Таким образом, случай  i = 0 подчиняется тому же критерию, что и случай  i < 0 или  i >0. Let's summarize the results obtained:

 <= 0выбираем пиксел (x i +1 , у i) - m H

 > 0 select pixel (x i +1, y i -1) - m D

" <= 0 выбираем пиксел (x i +1 , у i -1) - m D

About 15 - 20% of all couples experience infertility. In vitro fertilization (IVF) solves most of these problems, and constantly improving technologies minimize all possible risks and complications.

The procedure is performed according to strict indications and requires a certain examination the day before. How and when is IVF done, what should you be prepared for after the transplant? What should expectant parents know?

Read in this article

Indications for in vitro fertilization

To understand the essence of the IVF process, it is enough to decipher the term. “Extra” from the Latin “outside, outside”, “corpus” - “body”. That is, fertilization of the egg occurs not in the uterine cavity, but in artificially created conditions.

To carry out the IVF procedure, male (sperm) and female (ovum) germ cells are collected, merged and embryos are grown for 1 - 5 days. After this, they move to the woman’s uterus for subsequent gestation.

IVF is carried out in cases where, for some reason, fertilization cannot occur under natural conditions. These can be diseases, as well as social, psychological and other factors.

The main indication for IVF is. This diagnosis is established when a couple has unsuccessfully tried to conceive a child within a year, provided that the future parents are under 35 years old. Starting from 36, the interval decreases to six months. Infertility can be caused by various factors. Most often, IVF is performed for the following conditions and diseases:

• tubal factor (for obstruction or);
• endocrinological problems in which it is not possible to achieve natural conception even against the background of stimulation of ovulation and correction of hormonal levels;
• in the absence of ovaries or their inadequate functioning;
• with (sedentary male reproductive cells, a large number of atypical forms, etc.);
• if the problem is not identified.

In IVF, a sperm bank and surrogacy can be used. These are special forms of assisted reproductive technologies (ART). It is used when a man’s sperm is not suitable for work (for example, a complete absence of sperm), or the woman’s eggs do not mature, or she cannot bear a child for other reasons.

Contraindications to IVF

IVF is a serious procedure with a list of certain restrictions for its implementation. These include conditions when the likelihood of successful pregnancy and gestation is minimal, and there are contraindications from the woman’s health. The main ones include the following:

• Congenital malformations of the uterus and tumors (for example, fibroids), in which normal implantation and gestation are impossible.
• Malignant tumors of any location, including those in stable remission.
• Inflammatory processes in the acute stage. This applies to both the sexual sphere and banal ARVI, exacerbation of bronchitis, etc.
• Mental illnesses that are a contraindication to pregnancy.

Examinations before the procedure

IVF, like any pregnancy, must be taken seriously. This is an expensive procedure, each attempt of which takes away a piece of women's health. It is in the interests of the expectant mother and the whole family to achieve results as quickly as possible. To do this, you need to find out all the pitfalls and eliminate factors that can provoke failure.

The complex of examinations before IVF largely depends on the cause of infertility, as well as on the following factors:

• Has the woman had successful independent pregnancies?
• Have there been any premature births or undeveloped pregnancies?
• Age of the couple.
• Are there any disabled children in the family?
• What kind of IVF attempt is this and some others.

Based on this, a minimum (mandatory) examination plan can be identified. It is sufficient, for example, in the case of a specified tubal factor of infertility in a young couple (up to 35 years), if only the male factor is established and in some others.

The basic examination includes the following:

An additional examination is also always prescribed; it is necessary to detail the health of women and men. It includes the following:

• PCR of vaginal contents and cervical canal for chlamydia, mycoplasma, ureaplasma, trichomonas, gonococcus, HSV, HPV, CMV - for both sexual partners;
• blood test for hormones (FSL, LH, prolactin, estradiol, progesterone, DHEA sulfate, testosterone, 17-OPA);
• ELISA for rubella, cytomegalovirus, ;
• Ultrasound of the thyroid gland, pelvic organs;
• examination of the mammary glands (ultrasound examination up to 35 years of age, for older women – mammography);
• colposcopy and cervical biopsy if indicated.

The man must additionally provide spermogram data and an andrologist’s report. If pathology is detected, a testicular biopsy before IVF and determination of antisperm antibodies may be necessary.

If the proposed IVF attempt is not the first, or the woman has a history of undeveloped pregnancies or miscarriages, as well as for couples after 35 years of age, the list will be more expanded. It additionally includes the following tests as prescribed by a fertility specialist (only some of them can be performed):

• consultation with an endocrinologist;
• hysterosalpingography;
• hysteroscopy and endometrial biopsy;
• determination of antisperm antibodies in cervical secretions;
• medical genetic counseling with determination of a genetic passport;
• screening test for antiphospholipid syndrome (antibodies to cardiolipin, glycoprotein and others);
• testing for thrombophilia;
• SA-125.

How to do IVF step by step

All tests are prescribed by a fertility specialist at the center where the couple is going to undergo IVF. Each study has its own validity period. For example, a blood type is given only once, a general urine test is valid for only 7 days, a test for syphilis is valid for a month, etc. The doctor will tell you the most optimal timing and sequence of the examination.

After all the tests are ready, at the next appointment the specialist will indicate whether special preparation for IVF is needed, how and when is the best time to perform the puncture, etc.

Watch the video about IVF:

Preparation and stimulation of ovulation, sperm

If the cause of infertility does not lie in the woman, it is possible to collect eggs in a natural cycle for IVF. This makes the task easier for the couple, but somewhat more difficult for the doctor. This makes it more difficult to determine the most suitable day for cell collection. And in this case, you can only get one egg, or at most two, which subsequently reduces the chances of a successful attempt.

Most often they resort to superovulation, which occurs during stimulation. In this case, you can get several female germ cells at once. It is performed if ovulation is unreliable, the cycle is irregular, or there are some other circumstances. For this, various drugs and regimens can be used.

The most commonly used are the following:

• The short induction scheme is one of the most convenient and puts minimal stress on the woman’s body. All manipulations are carried out in one cycle. Ultrasound monitoring is carried out all the time and the dynamics of follicle and endometrial growth are monitored. This stimulation is closest to the natural cycle, so the likelihood of complications is minimal.
  • From the second to 12 - 14 days, hCG drugs are taken to stimulate follicle growth.
  • At the same time, induction with Clomiphene begins for 5 - 6 days.
  • On the 12th day, hCG (human chorionic gonodotropin) is administered to ripen the eggs.
  • After this, on the 14th day, with the appropriate size of the follicles, a puncture and collection of eggs is carried out, and after 2 - 3 days, the embryos are transferred into the woman’s uterine cavity.

• A long protocol implies a more serious intervention in a woman’s hormonal profile. It carries the risk of developing the syndrome, especially if performed on girls of the active reproductive period.
  • The onset occurs at the end of the cycle; for 18 - 20 days (from 21 days of the old to 11 of the new), it is necessary to take agonists of gonadotropic releasing hormones (GnRH), for example, Diferelin, Decapeptyl and others.
  • With the onset of menstruation, stimulation with FSH drugs is carried out.
  • Closer to 12-14 days, hCG is administered, after which the eggs are collected and, after a few days, the embryos are transferred into the uterine cavity.

• The super-long protocol is very similar to the previous one, but GnRH is administered over 4 to 6 months. This way you can achieve a reduction in some formations in the pelvis (endometriosis, fibroids, etc.) and increase the likelihood of successful pregnancy.

Sometimes during IVF, estrogens (estradiol) are additionally prescribed for endometrial growth, as well as gestagens (Duphaston, Utrozhestan and others) in the second phase.

For men, in most cases there is no need for such stimulation. From the entire ejaculate, you can always select the healthiest sperm and fertilize the eggs, including targeted fertilization (ICSI method).

How to perform follicular puncture

Puncture of follicles for the purpose of collecting eggs for IVF is carried out if the doctor confirms the normal size and location of the ovaries using ultrasound.

Manipulation most often occurs on an outpatient basis, under local or general anesthesia. Takes approximately 20 - 30 minutes. The procedure is performed under ultrasound guidance. This helps improve efficiency and avoid complications. This happens step by step like this:

1. A special vaginal sensor with an attached conductor and a needle is inserted into the vagina.
2. After this, the doctor takes aim and performs a puncture - piercing the follicles.
3. Using a needle, the contents are sucked out along with the eggs.
4. After this, the resulting material is analyzed in the laboratory, and the eggs are selected separately.
5. It is advisable to remain under the close attention of medical personnel in a medical institution for another 2 - 3 hours to monitor the woman’s general condition.

The process of fertilization during IVF

Fertilization in vitro (“in vitro”) can occur in several ways, which is influenced by the clinical situation. The following options are possible:

Option 1. It is used when there are no problems with sperm collection, they are mobile and in sufficient quantity. In this case, purified sperm are added to the selected egg (or more often to several at the same time). Insemination is carried out within 2 - 4 hours after cell collection.

Once the eggs and sperm are mixed, fertilization usually occurs within an hour. All this is carried out in conditions close to the human body (in temperature, nutrients, etc.).

Option 2. If it is impossible to isolate a sufficient number of sperm for fertilization, ICSI technology is used. In this case, the selected male reproductive cell is inserted directly into the egg using a special instrument.

Embryo cultivation

For the development of future embryos, the most comfortable conditions are created in the incubator. After 18 - 20 hours, it is assessed how normally the development of fertilized eggs begins. On the second day, they should contain special structures - pronucleoses, there should be two of them, identical to each other.

Deviations from the norm indicate some kind of developmental pathology; such cells are not allowed to develop further. All the rest continue to be cultivated.

Cell division occurs at a rapid pace. By the second day there are 2 - 4 pieces, and by the 3rd - 6 - 8. By the fifth day, a blastocyst is formed. It has a clear differentiation of cells, some of which further lead to the formation of the embryo, the other - the placenta.

Embryo transfer

Cell transfer into the uterine cavity can be performed at any time within six days. Before this procedure, their quality is assessed, which to some extent determines the prognosis of future pregnancy. Attention is paid to the shape and size of cells, internal structures (nuclei, nucleoli).

It is optimal to transfer good quality structures. This is not always possible, since development occurs according to its own laws. But even the transfer of cells of average and poor quality in most cases results in successful pregnancies and healthy children. The genetic material of the future baby may be good, and he will not have developmental disabilities.

Embryo transfer is carried out on an outpatient basis, takes about 10 - 15 minutes and does not require anesthesia. Often, to confirm the correctness of actions, everything is carried out under ultrasound control.

Progress of manipulation

The woman is placed in a gynecological chair, the cervix is ​​displayed in the speculum. Next, a special catheter with a diameter of several millimeters is inserted into the cervical canal. At the end it has a device similar to a regular syringe.

The biological fluid with the fertilized egg is placed in a catheter and then squeezed into the uterine cavity. Numerous studies and observations have shown that after the procedure, it is enough for a woman to remain in a horizontal position for 10 - 15 minutes.

The important question is how many embryos need to be transferred. On the one hand, the more, the higher the likelihood of a successful outcome of IVF. On the other hand, multiple pregnancy is a high risk for the woman and future children. In many countries, the number of embryos transferred is strictly limited.

Pregnancy after embryo transfer

In the following weeks, the cells that enter the uterine cavity begin to try to penetrate its wall and begin their further development. If the embryo has some genetic abnormalities, its implantation does not occur, or the pregnancy is terminated on its own before 12 weeks.

Only 10 - 14 days after the transfer of cells of the future embryo can one say with certainty whether their development continues in the uterus or not. To do this, you need to take a blood test for hCG. It is synthesized precisely by the cells of the embryo, if the latter grows normally.

To increase the likelihood of successful implantation, progestin drugs and estrogens are often prescribed.

Frequently asked questions before IVF

In each case, IVF has its own nuances. An individual approach is the key to the success of the procedure. Most women are concerned about the following questions:

• Is it painful to do IVF? Two procedures can cause discomfort: egg retrieval and embryo transfer into the uterine cavity. This is determined to a greater extent by the sensitivity of the woman herself. During egg retrieval, local anesthesia or intravenous anesthesia is sometimes used, which minimizes any discomfort.
• How often can IVF be done? In each case, the intervals between procedures are determined by the doctor. On average, a new IVF attempt is allowed after 2-3 months from the previous one. But, for example, if an unsuccessful pregnancy is terminated after 12 weeks, the period increases to 6 - 12 months. The same applies if severe ovarian hyperstimulation syndrome occurs during a previous attempt, etc.
• What are the guarantees during the procedure? It is believed that the probability of successful IVF is on average 30%, i.e. every third ends with the birth of a baby. But on an individual basis, the percentage can increase or decrease. For example, if a couple under 35 years of age has infertility due to tubal factor only and there are no other diseases or disorders, the probability of a successful attempt is more than 60 - 70%.

And, conversely, if the reason lies in the woman (hormonal, etc.), or there is some kind of hidden pathology, you can count on no more than 15 - 20%.

• Does IVF affect maternal health? In order to become parents, you have to sacrifice. The whole IVF procedure affects the health of the expectant mother.

The risks are as follows:

• With each new attempt, the risk of developing ovarian cancer in the future increases. Therefore, during the examination, it is necessary to take oncomarkers (CA-125 and others).
• Repeated attempts at IVF and stimulation can lead to disruptions in the menstrual cycle, problems with the mammary glands (MFCM and others), premature ovarian failure and menopause.
• An unsuccessful pregnancy is a serious stress for a woman, against the background of which diseases can also develop.

IVF is a chance for many couples to become parents. Despite the high level of medicine, only every third attempt ends successfully. The approach to each woman when performing IVF is individual, based on the general principles and experience of the doctor.

4 days ago

When is IVF the only way to get pregnant? Is this procedure painful and how long does it take (from the first consultation to the news of pregnancy)? Specialist of the reproduction center "Line of Life" Anastasia Mokrova explained how in vitro fertilization works and how many times it can be done.

Anastasia Mokrova Reproductologist, gynecologist at the Life Line Reproduction Center

1. There are cases when IVF is the only opportunity to get pregnant and give birth to a healthy child

The first is when a woman lacks both fallopian tubes (they were removed in previous operations due to an ectopic pregnancy, severe adhesions or inflammation). When they are not there, it is impossible to get pregnant naturally - only IVF.

The second case is a severe male factor, when either a chromosomal disorder is observed on the part of the man (and, as a consequence, a violation of spermatogenesis), or it is a late age, when stimulation of spermatogenesis will not lead to anything, or hormonal factors.

The third case is genetic. This means that the couple has severe chromosomal abnormalities that do not prevent them from living, but prevent them from giving birth to healthy children. In this case, an analysis is made not only for the existing 46 chromosomes that determine the genetic composition of the embryo, but also for a change in the karyotype, which for each pair can be decisive. Theoretically, such a couple can give birth to a healthy baby without intervention, but the probability of success is small.

2. IVF can help if a woman has depleted ovaries or wants to have a baby while in menopause

After 36 years, a woman is in late reproductive age (no matter how good she looks). The chance of conception is extremely reduced.

For some women, menopause or changes in the ovaries that reduce follicular reserve occur early. There is still menstruation, but the cells are no longer there, or they are of poor quality. In this case, an IVF program is carried out to obtain a healthy embryo and transfer it to the uterine cavity.

If a woman in menopause wants to become pregnant and bear a healthy child, we also resort to IVF. In this case, the egg of a healthy woman from 18 to 35 years old is taken, fertilized with the sperm of the patient's partner, and the embryo is implanted in her by IVF.

3. IVF has contraindications

There are very few contraindications for IVF, but they exist. This is a severe somatic pathology that is rare in women planning a pregnancy. Such patients with diseases of the heart, lungs, severe mental disorders usually do not reach reproductologists. However, if the disease is in remission and narrow specialists approve pregnancy planning, we work with the patient.

Oncological diseases are an absolute contraindication for stimulation for IVF. The oncologist must conclude that the patient is in stable remission.

4. IVF is possible at any age from the age of 18

According to the law of the Russian Federation, the age at which a woman can do IVF is not limited and starts at the age of 18. With age couples, the issue of pregnancy is discussed individually. Someone at the age of 50 can give birth to a healthy baby, while someone at 35 experiences difficulties.

5. The older the woman, the less likely it is to get pregnant with IVF

I have already said that after 36 years, a woman enters a late reproductive age. By the age of 40, even by IVF, the pregnancy rate is no more than 15. This is due to a decrease in the number of cells produced by the ovaries and a deterioration in their quality. For comparison, the probability of pregnancy with IVF before this age is about 70%.

6. Success in IVF is 50% dependent on the man

For the initial appointment with a reproductive specialist, I recommend that the couple come together. Based on the medical history, the doctor issues an individual list of examinations that a woman and a man need to undergo. Examining one woman does not make sense. It happens that a couple beats around the bush for a long time, trying to determine the problem on the woman’s part, and only then does some serious male factor become clear.

7. Short IVF protocol - the most comfortable for a couple

This is the most gentle program that requires minimal physical and material costs. At the same time, it has virtually no complications (including ovarian hyperstimulation), and is preferred by reproductive specialists all over the world. Especially for women with a good follicular reserve.

According to a short protocol, stimulation begins on days 2-3 of the cycle (before this, the doctor performs an ultrasound examination) and lasts about two weeks. When the stimulation is completed, the reproductologist sees follicles of a certain size and prescribes a trigger drug in order to carry out the puncture on time and bring the cells to maximum maturity.

The second stage is a transvaginal puncture. On the day of the puncture, the partner must also donate sperm.

The third stage is embryo transfer. Between the second and third stages, embryologists work to fertilize eggs and monitor the development of embryos. On the 5th-6th day of development, the couple is informed how many of them have been produced, what quality they are and how ready they are for transfer. A woman can find out about pregnancy 12 days after the puncture by doing a blood test for hCG.

I note that during IVF, a woman may have more abundant discharge. It may seem to her that she is about to start ovulating, but in reality this is not the case, because the whole process is controlled by a fertility specialist. During the IVF process, a woman is prescribed vitamin therapy and blood thinning medications to reduce the risks of hypercoagulation (increased blood clotting) and blood clots.

8. Before and during IVF, avoid heavy physical activity and adjust your diet

During the period of preparation for pregnancy, it is better for a man to avoid alcohol, saunas and hot baths. When entering an IVF program, a couple is not recommended to engage in heavy physical activity or have an active sex life - this can lead to the maturation of a large number of follicles, which will cause injury to the ovaries.

During IVF, I advise you to focus on protein foods (meat, poultry, fish, cottage cheese, seafood) and drink a lot (from 1.5 liters of liquid per day). This is necessary to ensure that you feel as comfortable as possible this month.

9. IVF procedure is painless

You don't have to worry about this. Stimulation injections are inserted with a tiny needle into the subcutaneous fat layer of the abdomen and may cause very mild discomfort (but not pain). As for transvaginal puncture, it is done under intravenous anesthesia for 5 to 20 minutes. Immediately after, heaviness may be felt in the lower abdomen, but under the influence of the painkiller, the discomfort goes away. On the same day, the patient is allowed to go home, and the next day she can work.

10. The average percentage of pregnancy as a result of IVF is 35-40%

These figures are relevant both for Russia and for Western countries. The success of IVF depends on the age of the patient and her partner (the higher, the smaller it is), the quality of his spermogram, previous manipulations with the uterus (curettage, abortion, miscarriages, etc.). The quality of the cells also plays a role, but there is no way to know about this before IVF.

11. IVF has no side effects if you trust a competent specialist

If the patient follows all the recommendations, the only side effect is pregnancy and the birth of a healthy baby. At the same time, it is important to trust a competent reproductive specialist. If stimulation is performed incorrectly, ovarian hyperstimulation, intra-abdominal bleeding, and ectopic pregnancy are possible (extremely rare if there was already a pathology of the fallopian tubes).

12. A cold without complications is not an obstacle to IVF

If you do not take antibiotics and antiviral drugs, and you do not have a high temperature, then a cold will not affect IVF in any way. This does not impair the quality of cells and embryos.

But if there are complications after ARVI, then the embryo transfer is temporarily canceled. A man is also not recommended to take antibiotics two weeks before donating sperm.

Previously, after IVF there were indeed many cases of multiple pregnancies. Now reproductive specialists around the world recommend one embryo for transfer. This is done in order to get a healthy child.

Multiple pregnancy is difficult for the female body to bear, and often ends in premature birth, which is risky for children.

It is much better for the patient to become pregnant after the second embryo transfer than to immediately give birth to twins with cerebral palsy.

14. Children after IVF are no different from children conceived naturally

Of course, these children also suffer from acute respiratory infections, ARVI, they have a certain heredity, they may have somatic diseases, but they are in no way inferior to other children in physical development and mental potential.

15. There are no restrictions on the number of IVFs

Typically, patients undergo IVF until results are obtained. In this case, embryos can be used from the first program, which are frozen and stored for as long as the patient wishes. You can try again after an unsuccessful IVF attempt the next cycle or every other cycle. It is not advisable to wait 3,4,6 months, but I advise you to discuss with the reproductologist the possible reason for the non-occurrence of pregnancy.

16. You can freeze your eggs “for the future”

Many couples do this. For example, if a man and a woman in a couple are 33-34 years old, and they are planning a child by the age of 40, it makes sense to think about freezing oocytes - by this time the quality of their own cells will deteriorate.

This is also done when a woman is not sure about a partner or wants to have a child for herself in the future. Then additional stimulation is not required, it will only be necessary to prepare the endometrium and conduct an examination of the body.

17. IVF can be done for free

To carry out IVF within the framework of the compulsory health insurance program, you need to contact your doctor at the antenatal clinic to receive a quota based on the results of tests and indications. This is done by doctors at the place of residence. I would like to note that in private clinics, reproductive specialists perform IVF only on the basis of ready-made referrals.

18. A single woman can also undergo an IVF program

For this purpose, donor sperm is used from a donor bank, which undergoes a thorough examination and is as fertile as possible.

19. There is a relationship between IVF and cesarean section

Often, women after IVF undergo a cesarean section during childbirth. This happens because their body has already undergone a single operation, there is adhesions in the abdominal cavity, and a somatic history. Plus, for many women after IVF, pregnancy is a very long-awaited pregnancy, they worry about everything and are simply not in the mood for a natural birth.

I am for natural childbirth (this is right for mother and baby). But it all depends on the indications at 38-39 weeks of pregnancy and the woman’s mood.

He may be a wonderful professional, but he will not suit the couple intuitively, you will be uncomfortable. This is a very important factor, as is the number of patients in the corridor. A doctor who sees 2-3 patients a day is probably not in great demand. If patients tell their friends about the doctor, share reviews and return to him for subsequent children, this is an indicator of the qualifications and human attitude towards the couple.

The choice of clinic is not of great importance, because completely different specialists can be gathered in one medical institution where IVF is performed.

The clinic may be young, but there is a real team working there. Price also does not play a determining role; in this case, advertising may simply work.

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