Thickness of the uterine scar for natural childbirth

A scar on the uterus usually appears as a result of surgical intervention, which can be performed for medical reasons.

Many women of childbearing age who have a scar on the uterus are interested in several questions:

1. How can this circumstance affect the course of pregnancy?
2. Is a natural birth possible if there is a scar on the uterus or is a cesarean section inevitable?
3. What is the outcome of childbirth with a uterine scar?

We will try to talk about all the features of childbirth for women who have such a defect.

The influence of the scar on the course of pregnancy and the upcoming birth

The degree of scar healing is of great importance, and depending on this circumstance, certain predictions can be made:

1. A healthy (or complete) scar - this is the one in which complete restoration of muscle fibers has occurred after surgery. Such a scar is elastic, capable of stretching as the gestation period increases and the uterus grows, and it is capable of contractions during contractions.
2. Incompetent (or defective) scar - this is one in which connective tissue predominates, and it is unable to stretch and contract like muscle tissue.

What operation caused the scar on the uterus?

Another aspect that should be taken into account is the type of surgical intervention, as a result of which operation the scar on the uterus appeared:

1. A scar after a cesarean section can be of 2 types:

1. a transverse one is done in the lower uterine segment, as planned during a full-term pregnancy, and it is able to withstand both pregnancy and childbirth, since the muscle fibers are located transversely, and therefore fuse and heal better after surgery;
2. longitudinal - performed during emergency surgery, bleeding, hypoxia (lack of oxygen) of the fetus, or up to 28 weeks of pregnancy.

2. If the scar appears as a result of conservative myomectomy (removal of nodes of a benign tumor - fibroids with preservation of the uterus), then the degree of its restoration depends on the nature of the location of the removed nodes, the access of surgical intervention (scar size), and the very fact of opening the uterus.

Most often, small fibroids are located on the outer side of the reproductive organ and are removed without opening the uterus, so the scar after such an operation will be more durable than when opening the organ cavity, when intermuscular nodes located between the myometrial fibers or intermuscularly are removed.

3. Scar as a result of perforation of the uterus after an induced abortion is also considered taking into account whether the operation was limited to only suturing the perforation hole (puncture), or whether there was also a dissection of the uterus.

The course of the postoperative period and the occurrence of possible complications

The process of restoration of uterine tissue after surgery will be influenced by the course of the postoperative period and the presence of possible postoperative complications.

For example, after a caesarean section the following may occur:

1. subinvaluation of the uterus - insufficient contraction of the organ after childbirth;
2. retention of parts of the placenta in the uterine cavity, which will require curettage;
3. postpartum endometritis - inflammation of the inner lining of the uterus.

Complications after conservative myomectomy may include:

1. bleeding;
2. hematoma formation (collection of blood);
3. endometritis.

Abortions and curettage of the uterine cavity performed after surgery traumatize the uterine cavity and do not contribute to normal scar formation. Moreover, they increase the risk of developing a defective scar.

All these complications will complicate the scar healing process.

Pregnancy period after surgery

Any tissue, including the wall of the uterus, needs time to recover after surgery. The degree of scar healing depends on this. For the uterus to restore the full functioning of the muscle layer, it takes 1-2 years, so the optimal time for pregnancy after surgery is no earlier than 1.5 years, but no later than 4 years. This is due to the fact that the more time passes between births, the more connective tissue grows in the scar area, and this reduces its elasticity.

That is why women who have undergone surgery on the uterus (whether myomectomy or cesarean section) are recommended to be protected from pregnancy for 1-2 years. And even before the planned conception, it is necessary to be examined for the consistency of the scar: based on the results, it will already be possible to predict the course of pregnancy and the birth itself.

Examination of the uterine scar

It is possible to examine the scar on the uterus after operations using:

1. Ultrasound examinations. If pregnancy occurs, this is the only possible type of research. Signs indicating scar inferiority are its unevenness, discontinuity of the outer contour, scar thickness less than 3-3.5 mm.
2. Hysterosalpingography - X-ray examination of the uterus and fallopian tubes after injection of a contrast agent into the uterine cavity. For this procedure, a special substance is injected into the uterine cavity, and then a series of x-rays are taken to judge the condition of the internal surface of the postoperative scar, its position, the shape of the uterine body and its deviation (to the side) from the midline. Using this method, it is possible to detect the inferiority of the scar, manifested in a sharp displacement of the uterus, its deformation, fixation to the anterior wall, as well as uneven contours and niches of the scar. However, this study does not provide enough information, and therefore is rarely used these days and is more often used as a method of additional examination.
3. Hysteroscopy - carried out using an ultra-thin optical device, a hysteroscope, which is inserted into the uterine cavity through the vagina (the procedure is performed on an outpatient basis under local anesthesia). This is the most informative method of studying the condition of the uterine scar, which is carried out 8-12 months after surgery, on the 4-5th day of the menstrual cycle. The fullness of the scar is indicated by its pink color, indicating muscle tissue. Deformations and whitish inclusions in the area of ​​the scar indicate its inferiority.

Girls, with what thickness of uterine scar can they be admitted to ER after a CS? Today I was at my third screening, until I asked the diagnostician to look at the scar, and no one would remember about it (The doctor said that the thickness of the scar at the moment is 3.2 mm, for 32 weeks this is the norm. But in the future, it can, of course, become thinner. In general, there are no indications for a repeat CS yet, but from time to time the stitch began to bother me: it aches, tingles... Something is scary for me. (((Tell me about your experience, how much can a scar become thinner in a month and a half (until the end of pregnancy).

The seam must be at least 3 mm. But here it seems that ultrasound can be wrong, as with the weight of the fetus. Three days before the birth, the seam was 2.5-3 mm, and after the operation the surgeon said that the seam was 1 mm. For some reason I didn’t ask him, the seam could have become so thin in three days.

The first cops, the second ones too, but I can’t decide on the cop!

From 2 mm they can calmly allow it, if the scar is wealthy, of course. There should be no niches. And I’ve seen cases where they gave birth with 1.5 mm.

I had 3.8 mm 10 days before giving birth, and 4.8 mm 3 weeks before that.

Did you give birth yourself? How do you feel about the EP after the CS?

Yes. Earth and sky are simple. Of course, in both cases it is not easy and painful, but an operation is an operation, and there are more possible complications, and the recovery takes longer, and it is psychologically difficult. And the EP was much easier for me, even though I had to go through 28 hours of contractions. Also, women in labor after a CS undergo a manual examination of the uterus immediately after birth, and this is under general anesthesia, which can also have consequences. But I heard that you can get by with an ultrasound. All the same, for me it’s better this way than with a cut abdominal cavity... I wouldn’t want any more CS :)

Got it, thanks for the answer. P.S. By the way, they didn’t do this to me - a manual examination, only an ultrasound.

Um... I probably wrote it incomprehensibly :) I’m talking about those who have ER after a CS, they undergo such an examination, they check the integrity of the walls of the uterus.

Ah, now it’s clear

I’m also still behind Er... now I’m sitting here reading everything... scary... preparing myself for the best)))

On the contrary, I am more inclined towards CS.

No, but the doctor who performed the CS for the first time asked me if I wanted to give birth myself, I said I wanted to and for now we stopped there... but what and how will probably be decided closer to the point. I’m gaining a lot and the baby will probably be big again... so it’s not a fact that there will be an EP.

By the way, I also gained a lot during this pregnancy! I thought the baby was big, I walked like a ball, rolling from side to side. The doctor says not to eat or drink (there will be swelling!). I’m trying to stick to a diet here... And today I came for an ultrasound, and they told me that the child was slightly underweight, everything is fine, but I need to eat more! I'm shocked

you know, at my last ultrasound at 25 weeks it was 800 grams somewhere, she said that it was normal and didn’t seem to be large, but remembering the last pregnancy the baby was 750 grams... but I don’t remember exactly the date, but it seemed the same and they immediately said it was large and gave birth to 4.100 at 38 weeks. so I think everything is still ahead. I just can’t get myself into a diet

If the baby is large, then with a scar they will most likely offer a CS

well, as if my doctor did a caesarean section, knowing that I had my first major one... only time will put everything in its place))))

It is believed that 3 mm. Only yours is probably not 3.2 cm, but 3.2 mm. The thickness of the uterine wall cannot be 3 cm!

Yes, of course, I got it wrong - 3.2 mm (I’ll edit it now)

I also had my first cesarean (emergency). I don’t even think about the second EP. Come on, these are risks. Fear for the stitch (because if God forbid, there will be severe internal bleeding and literally a few minutes to save the life of the mother and child), the entire process of contractions is under ultrasound control (if this is correct). And most likely, such a “pleasure” costs a lot in our country, because a woman in labor needs constant supervision. And God forbid, something happens - then you’ll reproach yourself all your life that because of your pride (“I didn’t give birth, I’m not a mother” and other cockroaches in my head) I lost... Netushka. It’s better to plan, calmly. But this is my personal opinion.

Scar on the uterus after cesarean section. Is it possible to get pregnant again and have a natural birth with a uterine scar?

Currently, a scar on the uterus is increasingly becoming a companion to pregnancy. How can this circumstance affect the course of pregnancy and the outcome of childbirth? Is it possible for a woman with a uterine scar to give birth naturally or is a caesarean section inevitable?

A scar on the uterus may be the result of:

1. previous caesarean section;
2. conservative myomectomy. Uterine fibroids are a benign tumor of the muscular layer of the uterus, which is removed while preserving the organ; this operation is called “conservative myomectomy.” This surgical intervention usually restores the ability of patients to conceive, but after the operation there is always a scar on the uterus;
3. perforation of the uterus (piercing the wall) during instrumental removal of the fertilized egg or uterine mucosa during abortion;
4. removal of a tube during a tubal pregnancy, especially if the tube is removed along with a small portion of the uterus from which it originates—the uterine angle.

The consistency of the uterine scar

For the course of pregnancy and the prognosis of the upcoming birth with a uterine scar, the nature of scar healing is important. Depending on the degree of healing, the scar can be considered complete, or wealthy, and inferior, or insolvent.

A scar in which complete restoration of muscle fibers has occurred after surgery is considered healthy. Such a scar can stretch with increasing gestational age and growth of the uterus; it is elastic and capable of contraction during contractions. If the amount of connective tissue in the scar predominates, then such a scar will be considered inferior, since the connective tissue is not able to stretch and contract the way muscle tissue can.

So, the degree of restoration of the uterine scar is influenced by the following factors:

1. The type of surgical intervention after which this scar was formed. If the scar is formed after a cesarean section, then the pregnant woman needs to know which incision was used to perform the operation. Usually, with full term and planned surgery, the incision is made in the transverse direction in the lower uterine segment. In this case, the conditions for the formation of a full-fledged scar that can “withstand pregnancy and childbirth” are more favorable than if the uterus was dissected longitudinally. This is due to the fact that the muscle fibers at the site of the incision are located transversely and after dissection they grow together and heal better than if the incision was not made along the muscle layer. A longitudinal incision in the uterus is mainly performed when emergency delivery is necessary (in case of bleeding, acute fetal hypoxia (hypoxia - lack of oxygen), as well as for caesarean section performed up to 28 weeks.
   A scar on the uterus can result not only from a cesarean section, but also from conservative myomectomy, suturing of uterine perforation, and removal of the fallopian tube.
   If a woman had uterine fibroids before pregnancy and she underwent a conservative myomectomy (removal of nodes of a benign tumor - fibroids while preserving the uterus), then the nature of the location of the removed nodes, surgical access, and the fact of opening the uterine cavity are important. Typically, small fibroids located on the outside of the uterus are removed without opening the cavity of the latter. The scar after such an operation will be more consistent than when opening the uterine cavity to remove intermuscular myomatous nodes located intermuscularly or between the fibers of the myometrium. If the scar on the uterus is formed due to perforation of the uterus after an artificial abortion, then the obstetric prognosis is more favorable if the operation was limited only to suturing the perforation without additional dissection of the uterine wall.
2. Duration of pregnancy after surgery. The degree of healing of the uterine scar also depends on the amount of time that has passed since the operation. After all, any tissue needs time to recover. The same goes for the wall of the uterus. It has been established that restoration of the functional usefulness of the muscle layer after surgery occurs within 1-2 years after surgery. Therefore, the most optimal is the onset of pregnancy in the interval from 1-2 years after surgery, but not later than 4 years, since a long interval between births leads to an increase in connective tissue in the scar area, which reduces its elasticity. Therefore, for women who have undergone surgery on the uterus, be it a cesarean section or a conservative myomectomy, obstetricians-gynecologists recommend contraception in the next 1-2 years.
3. The course of the postoperative period and possible complications. The process of restoration of uterine tissue after surgery also depends on the characteristics of the postoperative period and possible complications. Thus, complications of a cesarean section can include postpartum endometritis - inflammation of the inner lining of the uterus, subinvolution of the uterus (insufficient contraction of the uterus after childbirth), retention of parts of the placenta in the uterine cavity with subsequent curettage complicating the formation of a full-fledged scar.

Diagnosis of the condition of the uterine scar

A woman with a uterine scar needs to be examined for the consistency of the scar even before pregnancy in order to have complete information about the prognosis of pregnancy and childbirth. Outside of pregnancy, it is necessary to assess the consistency of the uterine scar in patients who have undergone operations associated with the risk of developing a defective scar. Such operations include conservative myomectomy with opening of the uterine cavity, cesarean section performed with a longitudinal incision on the uterus, surgery to suturing a perforation in the uterus after an abortion with opening of the uterine cavity. Examination of the uterine scar is possible using hysterosalpingography, hysterography and ultrasound. If pregnancy has already occurred, then diagnosing the condition of the scar is possible only with the help of dynamic ultrasound examination.

Hysterosalpingography is an x-ray examination of the uterus and fallopian tubes after the injection of a contrast agent into the uterine cavity. In this case, a contrast agent (visible on an x-ray) is injected into the uterine cavity, then a series of x-rays are taken. Based on their results, it is possible to judge the condition of the internal surface of the postoperative scar, determine the position, shape of the uterine cavity and its deviation away from the midline. With this method, the inferiority of the scar will be indicated by a pronounced displacement of the uterus, its fixation to the anterior wall, deformations, niches and uneven contours of the scar. Due to insufficient information content, this study is currently used quite rarely or as an additional research method.

The most informative instrumental method for studying the condition of a uterine scar is hysteroscopy - examination of the uterine cavity using an ultra-thin optical device, a hysteroscope, which is inserted into the uterine cavity through the vagina.

After surgery, hysteroscopy is performed after 8-12 months and on the 4-5th day of the menstrual cycle. Currently, there are small-diameter hysteroscopes that allow this procedure to be performed on an outpatient basis and under local anesthesia. The pink color of the scar during hysteroscopy indicates its usefulness and consistency, it indicates muscle tissue, and whitish inclusions and deformations in the area of ​​the scar indicate its inferiority.

Complications after conservative myomectomy may include bleeding, hematoma formation (collection of blood), and endometritis.

Also, unfavorable factors for the formation of a postoperative scar include abortions and curettage of the uterine cavity, performed after a previous operation, which injure the uterine cavity. They significantly worsen the prognosis of the upcoming birth and increase the risk of developing a defective scar.

The condition of the uterine scar is usually assessed during pregnancy using ultrasound.

Signs indicating the inferiority of the scar are, for example, its unevenness, discontinuity of the outer contour, thinning of the scar to less than 3-3.5 mm.

Features of childbirth with a uterine scar

Just a few years ago, many obstetrician-gynecologists were guided by the slogan: “Once a caesarean section, always a caesarean section” when determining delivery tactics.

However, at present, the opinion of experts has changed. After all, a caesarean section was and remains a serious surgical procedure, after which serious complications can arise. Despite the proven methods of surgical delivery, it should be recognized that the risk of postoperative complications is significantly higher compared to patients who gave birth through the vagina. And the process of recovery of the body after vaginal birth is much faster.

Complications after surgery can be associated both with the surgical procedure itself and with the method of anesthesia. The highest risk is thromboembolic complications (during any operation there is a risk of blood clots that can cause blockage of blood vessels), severe bleeding, damage to neighboring organs and infectious complications.

Taking this into account, over the past 10 years, doctors have been attempting to deliver women with a uterine scar through the natural birth canal.

To resolve the issue of the method of delivery, all pregnant women with a uterine scar are advised to undergo planned prenatal hospitalization at 37-38 weeks of pregnancy for a full comprehensive examination. In the hospital, an obstetric history is analyzed (number and outcomes of pregnancies), concomitant diseases are identified (for example, from the cardiovascular, bronchopulmonary system, etc.), an ultrasound examination is performed, including an assessment of the postoperative scar, and the condition of the fetus is assessed (Doppler - study of blood flow, cardiotocography - study of fetal cardiac activity).

Indications for natural childbirth with a uterine scar

Natural childbirth is possible if the following conditions are met:

1. The pregnant woman has only one significant scar on the uterus.
2. The first operation was performed for “transient” indications; this is the name for indications for surgery that first arose during a previous birth and may not necessarily appear in subsequent ones. These include:
3. chronic intrauterine fetal hypoxia is an insufficient supply of oxygen to the fetus during pregnancy. This condition can occur for various reasons, but will not recur in the next pregnancy;
4. weakness of labor - insufficiently effective contractions that do not lead to dilatation of the cervix;
5. breech presentation - the fetus is positioned with its pelvic end towards the exit of the uterus. This position of the fetus in itself is not an indication for surgery, but serves as a reason for cesarean section only in conjunction with other indications and does not necessarily repeat during the next pregnancy. Other malpositions of the fetus, such as transverse position (in which the baby cannot be born spontaneously), may also not be repeated during the next pregnancy;
6. large fruit (more than 4000 g);
7. premature birth (births occurring before the 36th-37th week of pregnancy are considered premature);
8. infectious diseases identified in a previous pregnancy, in particular an exacerbation of a herpetic infection of the genitals shortly before childbirth, which was the reason for a cesarean section, do not necessarily occur before the next birth.

When a postpartum woman is discharged from the maternity hospital, the doctor is obliged to explain to the woman exactly what indications the cesarean section was performed for. If the indications for a cesarean section were related only to the characteristics of the first pregnancy (abruption or placenta previa, clinically narrow pelvis, etc.), then the second pregnancy may well (and ideally should) end in natural birth.

Spontaneous births in pregnant women with a uterine scar should take place in an obstetric hospital, where round-the-clock highly qualified surgical care is available, and there are anesthesiological and neonatal services. Childbirth is carried out with constant cardiac monitoring. This means that special sensors are connected to the pregnant woman directly during childbirth. One of them records the contractile activity of the uterus, contractions, and the other records the fetal heart rate. Such monitoring makes it possible to determine the condition of the child during childbirth, as well as the strength of contractions. Natural childbirth in a woman with a uterine scar should be carried out in such conditions that in the event of a threat of uterine rupture or if the uterus ruptures along the scar, it is possible to provide surgical assistance in a timely manner, within the next few minutes.

If scar deficiency is suspected during pregnancy, the patient should be hospitalized long before birth, at 34-35 weeks of pregnancy.

Indications for surgery

If any signs indicate an inferior scar on the uterus, childbirth should be operative - it is only necessary to determine the timing of delivery depending on the condition of the fetus and mother.

Indications for repeat caesarean section are:

1. A scar on the uterus after a corporal cesarean section, or an operation performed with a longitudinal incision in the uterus (in this case it has a very high risk of failure).
2. Scar after two or more operations.
3. Scar failure, determined by symptoms and ultrasound data.
4. Location of the placenta in the area of ​​the uterine scar. If the placenta is located in the area of ​​a postoperative scar, then its elements are deeply embedded in the muscular layer of the uterus, which increases the risk of uterine rupture when it contracts and stretches.

If a woman with a uterine scar gave birth through the vaginal birth canal, a mandatory postpartum event is a manual examination of the walls of the postpartum uterus to exclude incomplete uterine rupture along the scar. This operation is performed under intravenous anesthesia. In this case, the doctor inserts a hand in a sterile glove into the uterine cavity, carefully feels the walls of the uterus and, of course, the area of ​​the postoperative scar on the uterus. If a defect is detected in the area of ​​the scar, if it has partially or completely ruptured, in order to avoid intra-abdominal bleeding, urgent surgery is required to suture the area of ​​the rupture, which threatens the life of the mother.

Possible complications

A scar on the uterus can cause some complications during pregnancy. Most often, there is a threat of termination of pregnancy at different times (found in every third pregnant woman with a scar on the uterus) and placental insufficiency (i.e., the supply of insufficient oxygen and nutrients through the placenta). Often this pathology occurs when the placenta is attached to the area of ​​a postoperative scar and appears due to the placenta being attached not in the area of ​​full muscle tissue, but in the area of ​​altered scar tissue.

However, the main danger a woman faces during childbirth is uterine rupture along the scar. The problem is that uterine ruptures in the presence of a scar often occur without significant symptoms.

Therefore, during childbirth, the condition of the scar is constantly monitored. Experts determine it by palpation through the anterior abdominal wall, that is, by palpating the scar area. Despite the contractions, it should remain smooth, with clear boundaries and practically painless. The nature of bloody discharge during childbirth (there should be little of it) and the mother’s complaints of pain are important. Nausea, vomiting, pain in the navel, weakening contractions may be signs of the beginning of a scar rupture. To objectively assess the condition of the scar during childbirth, an ultrasound examination is used. And if signs of its inferiority arise, which primarily include weakness of labor or any other complications during childbirth, they proceed to delivery by cesarean section.

Thus, in a woman with a uterine scar, spontaneous childbirth is permissible only if the scar is intact and the mother and fetus are in normal condition; they should be carried out in large specialized centers, where the woman in labor can be provided with highly qualified assistance at any time.

Victoria Khaikina, obstetrician-gynecologist, Moscow