Features of cervical dilation

Although cervical dilation is a normal aspect of childbirth, expectant mothers may find it confusing. Gaining an understanding of how it operates can help calm fears and make the procedure seem more doable. This is a crucial indication that labor is moving along because it’s the body getting ready for the baby to arrive.

As labor draws near, the cervix, or lower part of the uterus, starts to open up. There are stages to this dilation, and every woman will experience it differently. While it may happen more quickly for some, for others it may happen gradually over time.

Women and their families can feel more prepared and confident during labor if they are aware of what to expect during cervical dilation. The main features of cervical dilation will be discussed in this article, along with its stages, factors that affect it, and how to spot its progression.

What is happening?

The fundus, the widest portion of the uterus, and the neck, the narrowest, are shaped like a tied bag. Since the cervix is a round muscle, it can initially contract, close, and open. There is a small cervical canal inside the cervix; one end of the canal exits into the uterus, and the other end enters the vagina. A mucous plug covers the cervical canal during pregnancy with the intention of keeping bacteria, viruses, and other undesirable "guests" from ascending from the vagina and into the uterine cavity.

The length of the cervix gradually decreases during pregnancy. If it is approximately 3.5–4 centimeters long when not pregnant, it will start to shorten, mature, and smooth out to 1 centimeter in the final weeks before delivery.

The cervix begins to open under the pressure of the fetal head after it descends into the uterine cavity below. Also, special hormones and enzymes are actively involved in this process, and psychological attitude is also of great importance. There are known cases when, due to fear of childbirth, a woman"s cervix does not open even after regular labor contractions begin. Dilation is necessary so that the fetus"s head can pass through the canal inside the cervix during childbirth, and then the fetus itself. From a tightly closed cervix, as labor contractions develop, it expands to 10-12 centimeters. This is called full dilation. After it, the child begins its journey into this world.

A vital sign that the body is ready to give birth is cervical dilation, which occurs during childbirth. The cervix gradually opens during labor to make room for the baby to pass through the birth canal. Pushing can only start once the cervix has dilated to a diameter of approximately 10 centimeters. This process usually occurs in phases. Cervical dilation can occur at varying rates and experiences for women, so it’s critical to recognize the symptoms and know what to anticipate during labor.

Dilation mechanisms

Labor can start at any moment if the cervix is mature, soft, slightly open, and shortened. Hospital physicians are working to prepare the cervix if the time is right but maturation does not take place. The cervical canal should become softer and more elastic even before childbirth, taking on the shape of a funnel as a result of the internal os opening. Women giving birth for the first time and women who have given birth before have slightly different dilatation mechanisms.

In primiparous women

In women giving birth for the first time, the internal os opens first, and only after that the cervical canal begins to expand. The external os remains closed. The wider the canal becomes, the shorter the cervix becomes. When the cervix smooths out and no longer protrudes forward, the external os still remains closed. Its edges stretch and become thinner. When a woman gives birth, they diverge in different directions. Each labor contraction increases the dilation. It is completely impossible to check the degree of dilation at home. This is done by a gynecologist during a vaginal examination. But a woman can be guided by signs and symptoms that indicate that the process has started.

First of all, this is the onset of regular, rhythmic, periodic contractions that get stronger as the labor progresses. Mucus plug removal is possible. When the cervical canal is already dilated, either completely or partially, it emerges. The plug has a jelly-like appearance, resembles a clot of milky, yellowish mucus, and may have blood streaks and impurities.

It is not always the case that the cervix is open when the contractions start. She has a lengthy list of tasks ahead of her. Usually, the process takes longer with a first birth.

The latent period of contractions, when uterine spasms are repeated every 30-20 minutes, can last up to 8 hours. The woman in labor should end up in the maternity hospital when contractions confidently return every five minutes. With such intensity of uterine contractions, most often the expansion of the external os is about 3-4 centimeters, but everything is individual. In the period of active contractions, the primiparous woman giving birth should spend about five more hours. The speed of opening of the cervix of the female reproductive organ increases, and during this time it opens on average to 7-8 centimeters. The final period is transitional. Usually it lasts up to an hour and a half, and the dilation becomes maximum, complete.

Reviews state that each contraction starts with tension in the lower back and gradually moves to the lower abdomen, the middle section of the uterus, and the peritoneum. These sensations intensify during the gradual dilation.

Obstetricians and physicians monitor dilation of the cervix. There is no need to keep an eye on the woman while she is at home. A vaginal examination will be performed if the amniotic sac is intact upon admission to the maternity hospital, as well as when the water breaks and, if needed, at other times. When a woman is admitted to a maternity hospital with an early water break, her cervix is checked to ensure that there is no infection inside the uterus. However, unless there is an immediate medical necessity, no manual or instrument examination is performed.

In women giving birth again

When a woman gives birth again, the "muscle memory" is activated and the birth canal is typically ready beforehand. One characteristic of the natural expansion mechanism is the nearly simultaneous revelation of the internal and external pharynx necks. This implies that expansion will happen both inside and outside when regular contractions start. This characteristic explains why all generic periods get shorter when giving birth more than once.

Typically, the second, third, and subsequent births go by more quickly. Consequently, you should visit the maternity hospital a little earlier than during the first birth after a woman manages to identify the birth fights; it is best to do so in the ten-minute interval between uterine spasms.

Following a vaginal examination, doctors will learn what transpires in the cervix when the patient is admitted to the hospital. The external pharynx is typically opened in multiparous women at the end of the baby’s gestation period, bypassing the obstetrician-gynecologist’sfingertip. In the final few weeks leading up to the anticipated birth date, the cervix is examined for maturity.

"Finger" method

Many women who are in an "interesting position" have heard that obstetricians evaluate the degree of cervical dilation in their fingers. But it can be difficult for the average person to understand whose fingers exactly are used as the basis for the measurement system and how much is that in the centimeters we are used to. We are talking about a conventional unit of measurement of the degree of cervical dilation, which is proudly called an obstetric finger. There are only two ways to measure dilation – do a transvaginal ultrasound and examine the cervix manually. The second method is considered faster, and therefore it is actively used by obstetricians all over the world. The examination is carried out as needed in the maternity hospital or in a consultation during examinations at later stages of pregnancy. The midwife carefully inserts several fingers into the vagina, not counting the thumb, since it is short. The hand should be in a sterile glove, if necessary, the doctor can use medical petroleum jelly. How many fingers the uterus "lets in" is how great the dilation is. The more the cervix dilates, the more fingers will pass through.

For this reason, in the later stages, physicians frequently report that a fully developed cervix dilates one finger. Additionally, upon admission to the maternity hospital, where the labor process is monitored, the patient can already report a dilation of two to three fingers.

And how much is that in centimeters? According to generally accepted international practice, one conventional obstetric finger is equal to 1.5-2 centimeters. The error of half a centimeter is due to different fingers of different health workers. Thus, when a woman arrives at the maternity hospital with contractions recurring every five minutes, most often it is registered dilation of 2 fingers, that is, the actual dilation is approximately 3-4 centimeters, and this means that the woman has not yet entered into active contractions. Active uterine spasms, repeated every 2-3 minutes, usually lead to an expansion of 3-3.5 fingers, which corresponds to 6-7 centimeters. Full dilation of the cervix corresponds to the concept of "more than 4 fingers". There are only four free fingers that can be inserted (minus the thumb, as we remember). And therefore, it is not physically possible to accurately measure the full dilation and state whether five or seven fingers pass.

When "more than four fingers" dilate, the medical staff and the laboring woman should know it’s time to move the patient to the delivery room because pushing has started.

Preparation before childbirth

Preparation of the cervix begins if by the 39-40th week of pregnancy, doctors recognize it as immature or not mature enough. In order to make the appropriate conclusion, one finger method will not be enough. Bishop"s assessment system is used for correct conclusions. It includes several important signs that are taken into account during a vaginal examination. For each sign, 0 to 2 points are awarded. A cervix of 8 points on the Bishop scale is considered mature. In this case, the cervix is ​​soft, ready for faster and easier expansion during labor, the length of the cervix is ​​less than a centimeter, the external os allows 1-2 fingers to pass through, the cervix itself (its contraction ring) is located exactly in the middle, not deviating either to the right, or to the left, or back, or forward.

Preliminary medical interventions are performed if the cervix’s maturity score is less than eight. In this instance, the number of points and the gestational age determine which preparation techniques are used.

A cervix that received less than 3 points according to the Bishop scale as a result of examination is considered immature and requires the earliest possible start of using medications and mechanical means to accelerate maturation.

On the Bishop scale, 3–4 points correspond to inadequate maturity. The woman can be left alone if her gestational age permits, as the cervix can still ripen naturally. If there is still one week until delivery, the cervix will have reached 5-8 points and its condition won’t need to be corrected.

Inpatient preparation comes in two flavors: mechanical and medicinal. A Foley catheter and kelp sticks are examples of mechanical techniques. Medications are typically hormonal medications in the form of tablets, suppositories, or gel that is applied directly to the cervix. The doctor’s job is to choose the approach. Women are frequently advised to start taking "No-Shpa" at 38–39 weeks or even earlier because this antispasmodic medication efficiently relaxes smooth and round muscles, hastening the smoothing and maturation process.

Walking and light housework are regarded as beneficial activities during the past few weeks. The likelihood that a woman’s cervix won’t open on its own without assistance increases with her level of sedation. Gymnastics is beneficial; a series of Kegel exercises in particular.

In order to get the cervix ready for labor, doctors take additional steps if it does not open and does not soften by 40–41 weeks.

Foley catheter

A piece of medical equipment for bladder catheterization. Certain types of catheters are used to induce labor, specifically catheter No. 18. It’s a thin silicone-coated latex tube. At the distal end, there is a tiny balloon. The balloon is filled with 10 milliliters of saline or water and the tube is inserted into the cervical canal through the vagina. Via the catheter, a tiny quantity of saline is also inserted into the uterine cavity. The balloon expands to its full size and presses against the cervix, which causes it to mechanically expand.

The catheter is left in place for a full day. The cervix is not installed if it is generally immature. Unfortunately, this process is not always successful and is extremely painful. In over 50% of instances, the cervix remains closed.

These days, the technique is rarely employed, primarily when a woman cannot safely use another method.

Laminaria

Sticks of dried kelp seaweed are about 6 cm long, and their thickness varies from 3 to 9 mm. The doctor determines which size to choose, basing his choice on the actual condition of the cervix at the time of preparation. Sticks are inserted into the cervical canal. Laminaria has the property of expanding and increasing in volume upon contact with liquid media. The stick in the canal begins to swell, the cervix, as a result, expands mechanically. In addition, algae stimulate the production of prostaglandin F2A. This substance at the biochemical level promotes faster shortening and smoothing of the cervix. Sticks are installed for 24 hours. After this time, they can be removed. Whether it is necessary to install new, wider ones, is decided by the doctor.

Although not as painful as inserting a Foley catheter, this procedure is still very apparent. Furthermore, the method’s effectiveness is not 100%; in half of the cases, the sticks do not produce the desired result.

Medicines

In contemporary obstetrics, this is the most widely used and well-liked technique. Apart from "No-Shpa," whose antispasmodic action was previously mentioned, suppositories such as Buscopan or Papaverine might also be recommended. Estrogen and prostaglandin-related medications make up the majority of hormonal agents used in hospitals under medical supervision. The precise names of the medications, along with their dosage and frequency of use, are chosen specifically for each woman. The technique is thought to be very successful.

Possible problems

Cervical problems can occur during pregnancy as well as during childbirth. More information about the potential outcomes should be provided so that the woman is able to handle a variety of circumstances.

Before childbirth

When the cervix shortens and smoothes too soon, like in the second trimester, this is referred to as isthmic-cervical insufficiency (ICI), or functional insufficiency of the cervix.

Depending on the circumstances, a woman may be advised to install an obstetric pessary or have surgical sutures placed on her cervix in order to prevent premature birth.

If all of the doctor’s advice is followed, a woman has a good chance of bringing her pregnancy to term with these devices.

In labor

When labor begins, the cervix can behave differently, and the process does not always occur exactly as described in courses for expectant mothers or in books for women in labor. Dilation can proceed too quickly. This creates the preconditions for rapid labor. They pose a real danger to the child and mother, because they often end in serious birth injuries. Most often, this occurs in women with a weakened round muscle of the cervix – those who have given birth many times, those who are pregnant with twins or triplets, with ICI, which was mentioned above. Premature birth is often accompanied by an excessively rapid opening of the external os. Also, such an anomaly can be a consequence of labor stimulation as such.

Examine closely if there is any labor activity that is not coordinated in this situation. They attempt to assist the woman by giving her medication, which in part slows down the labor process overall and the opening in particular.

Another common complication is primary weakness of labor forces. With it, the opposite processes occur – contractions are discoordinated, weak or absent, or are present, but the cervix opens very slowly, at an insufficient rate. In this case, amniotomy is used – a puncture of the amniotic sac, and if this does not help, oxytocin and antispasmodics are injected according to a certain scheme. If this is also ineffective, they can perform manual opening of the cervix, but this is a very painful and traumatic procedure. It is carried out mainly if the woman in this situation flatly refuses an emergency cesarean section. Problems with dilation are often experienced by women who give birth at a very young age (before 18 years), as well as after 37 years, especially if a lot of time has passed since the woman"s first birth. The cause of weakness can be strong fear and the resulting muscle clamps at the psychosomatic level. In women giving birth again, primary weakness develops less often than in women giving birth for the first time. The problem can also be rooted in a complicated obstetric history, for example, previous abortions. Often, the reason for the lack of proper dilation lies in hormonal imbalances.

Stage of Cervical Dilation	Description
Latent Phase (0-3 cm)	Cervix begins to open, contractions are mild and irregular.
Active Phase (4-7 cm)	Dilation speeds up, contractions become stronger and more regular.
Transition Phase (8-10 cm)	Cervix fully dilates, contractions are intense and frequent.

Cervical dilation is a crucial step in the labor and delivery process. Expectant moms can feel less nervous and more prepared for the experience if they know how it goes. Because every woman’s body is different, there can be significant variations in the timing and stages of dilation.

It’s critical to pay attention to your body and maintain contact with your healthcare provider. Throughout the various stages of labor, they will support you and provide interventions as needed. Knowing what to expect and being well-informed can significantly impact your delivery experience.

Recall that giving birth is a normal process that your body can handle. Whether your labor goes quickly or takes a while, the outcome—the birth of a new life—is worthwhile. As you set out on this amazing journey of becoming a parent, surround yourself with people who will support you and have faith in the process.

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