Cascata de intervenções médicas durante o parto

In our culture, there has been a tendency to turn pregnancy and childbirth into a medical experience. One intervention can lead to another in a cascading sequence of questionable procedures, many made necessary only because of a previous intervention.

We are indeed lucky to live in a time when medical aids to labor and delivery exist, but medical interventions such as labor induction, pain relief, and cesareans—measures that have saved many lives—have been overused.

It can be helpful to get familiar with many of the tests and interventions associated with childbirth in order to know when they are warranted and when they should be avoided.

Tests in Late Pregnancy
As you approach, or pass, your projected due date, your practitioner may suggest that you have one or more tests to assess the well-being of your baby, particularly if there is any reason to believe his health might be compromised.

One of the most common reasons practitioners worry about this is simply because of post maturity, which is when a baby remains in the womb past the time of his projected due date.

Truly post-mature babies can sometimes receive inadequate nourishment due to placental failure. Therefore, many doctors automatically give women one or more of these tests as soon as they reach their due date. This is particularly true for any women who have been designated high risk.

Here are some of the tests commonly given in late pregnancy:

* Fetal movement counting, or the kick test. This is a do-it-yourself test. You set aside a several-minute block of time at the same time each day. Your practitioner will instruct you to begin timing with the first movement you feel, recording how long it takes to feel ten movements. This test is only effective as a rough screening device and can not predict the likelihood of problems. This is because the test is extremely subjective—fetuses, like adults, are highly variable. You might choose a time to measure movements that coincides with a nice long nap, for example, resulting in very little movement.
* The non-stress test (NST). The NST will be conducted in your practitioner’s office, or in a hospital. You will sit in a chair, and an ultrasound transducer will be placed on your abdomen. You will be asked to signal every time you feel the baby move. The change in the baby’s heart rate as a result of these movements will be observed. This test often causes false alarms, where the baby seems to be nonreactive, as often as 75 percent of the time. One highly esteemed source of information, A Guide to Effective Care in Pregnancy and Childbirth, remarks, “One can only speculate as to why the [non-stress test] continues to be used in such an extensive way…and why the results from the only four randomized trials that have been published are so widely disregarded by many obstetricians.”
* Biophysical profile (BPP). This test combines the non-stress test with other evaluations of the fetus, all using the ultrasound to obtain results. Fetal movement, heart rate, breathing movements, muscle tone, and amniotic fluid levels are each assessed. The fetus is given a score from 0 to 2 for each element. A score of 8 or higher suggest the baby is doing well. A score of less than 6 is of concern. This test is more accurate when it detects either high- or low-range scores. Scores in the mid-range are less accurate. Studies testing the effectiveness of the BPP on women in high-risk categories did not show an improvement in birth outcomes.
* Contraction stress test (CST) or oxytocin-challenge test. During the CST, the baby is subjected to minor contractions in order to see how she reacts. This will help determine how the baby is doing in the womb, as well as how she may react to the real contractions of the upcoming labor. Because this test can bring on actual labor, it cannot be administered to women who have had preterm labor, placenta previa, multiple fetuses, or ruptured membranes. This test is normally conducted in a hospital. Ultrasound will be used to detect the baby’s heart rate. The mother will be given a small dose of pitocin. If the baby is doing well, her heart rate will not change significantly during contractions, and will return to normal quickly after each one. This test has a high incidence of false positives, where the results erroneously indicate that the baby is not doing well. It is not an accurate indicator of an acute emergency situation, where a baby should be delivered via C-section right away. However, it can effectively alert a practitioner to keep a closer eye on a baby during labor.

Although most of these tests do not have the potential to directly harm a baby (except for the CST which can bring labor on), the danger in using them lies in the rate of false positives. This can motivate practitioners to recommend emergency cesarean, unnecessarily subjecting the mother and baby to the dangers of major surgery. This is especially true if the test is given as a matter of routine, rather than because of a specific concern.

Since late pregnancy tests have such a poor track record of predicting trouble even in high-risk pregnancies, taking them may set up a woman for unnecessary worry at a time when she needs to rest, relax, and prepare for the birth ahead.

Labor Induction
A decision to begin labor at a given time, rather than leaving it to nature, is referred to as labor induction.

Labor is induced for a variety of reasons, ranging from medical necessity to convenience. Some physicians are very concerned about the consequences of babies who are still in the womb past their due date. Others worry about the possibility of infection in a woman whose water has broken, but who has not yet gone into labor. Sometimes it is the woman herself who is impatient and decides to use natural stimulation, such as taking long walks, to get things going.

Another term commonly used is labor augmentation. Augmentation is meant to speed things up, either because it seems as though labor has come to a halt, or because the woman or her health care provider want things to go faster. Today many women have their labor augmented with some type of drug, despite the fact that both the American College of Obstetricians and Gynecologists and the Food and Drug Administration do not approve of the use of inductions drugs for this procedure.

Here is a rundown of induction methods commonly used by hospitals:

* Stripping the membranes. The birth attendant inserts a finger between the cervix and the membranes of the amniotic sac to separate it from the uterine wall. This method is known to be generally safe, though not always effective. It is used by both doctors and midwives. You may experience some discomfort from this procedure.
* Prostaglandin creams or gels. These are applied to a woman’s cervix to help soften or ripen it. If a woman has gone beyond her due date and her cervix is still not ripe, she may be offered a prostaglandin cream in her practitioner’s office. It is also used in hospitals prior to chemical induction. The application itself is painless.
* Breaking the amniotic sac. The practitioner uses a hook-shaped instrument to pierce the amniotic sac and release the fluid, which sometimes causes labor to begin or speed up. This has become routine procedure prior to a chemical induction. Some women report that they feel a sharp pain when the sac is broken.

When is labor induction really necessary? Experts vary in their estimates, but most agree that only 5 percent of labors require chemical induction read Medical Indications for Inducing Labor to learn about solid reasons to use chemical induction.

Labor is induced for many other reasons, including:

* Because a physician would like to speed labor up
* Because a woman seems tired to the practitioner
* To get labor started once a woman’s water has broken (even though there is no sign of infection)
* To avoid larger-than-average birth size associated with gestational diabetes
* Because a woman has gone past her due date
* Because a woman (or her physician) has decided she would like her baby to be born on a certain date

The biggest problem with labor induction is its very concept. Why do we think we know better than Mother Nature when a baby should leave the womb? The forces that trigger birth are still poorly understood.

Worse, the use of induction and augmentation can easily lead to other interventions for the following reasons:

* Because chemical induction can produce contractions that can begin suddenly and are much stronger than natural contractions, and potentially put the baby in a state of distress, the baby’s heart rate and respiration must be continuously monitored. Being hooked up to an Electric Fetal Monitor (EFM) increases the chances of surgical intervention, which we will discuss in the next section.
* The contractions produced by chemical induction are almost always too painful for a woman to manage without medications. Epidural anesthesia requires an IV line for hydration, and a urinary catheter. Epidural anesthesia, in turn, increases the chances of surgical birth.
* Reduced mobility, due to the IV, catheter, anesthesia line, and EFM. A woman whose labor is induced usually cannot move around or change labor positions, which can make labor last longer.
* Increased chance of cesarean. Distress to the baby caused by high levels of pitocin, combined with slowed labor and the mother’s exhaustion, often results in the need for cesarean.

Electronic Fetal Monitoring
Prior to the 1970s, the baby’s heart rate was checked intermittently, every 15 minutes or so, by a maternity nurse using a fetal stethoscope or a handheld Doppler ultrasound monitor on the laboring mother’s belly. When the EFM was first invented, it was heralded as an incredible timesaving device that could free the nurse up to minister to her patients in other ways. These days, the use of EFMs has become routine in most hospitals.

The idea behind continuous monitoring, rather than intermittent stethoscope monitoring, is that care providers receive immediate notification if there are any serious changes in the baby’s heart rate.

There are two types of EFMs: external and internal. When the external type is used, two large straps or wide elastic bands are placed around your belly. One of them has a Doppler device on it that uses ultrasound to measure the baby’s heart rate. The other strap has a pressure-sensitive device that detects your contractions.

The internal type of monitor, which is more accurate, requires that water be broken. A wire is placed inside the vagina and attached to the baby’s scalp with electrode clips. A catheter is put inside the uterus to measure contractions.

Several well-conducted studies have not been able to show a benefit to using a constant EFM rather than intermittent monitoring, such as with a stethoscope, for a normal-risk pregnancy. There was no improvement in death rate or Apgar scores for infants who were constantly monitored. The American College of Obstetricians and Gynecologists now supports a policy of using intermittent monitoring.

In spite of this fact, most hospitals continue to use continuous EFM. One reason for this may be that nurses and doctors are no longer well trained in interpreting intermittent monitoring. Another reason has to do with the allocation of manpower. It takes more time to check a woman every 15 minutes than to use an EFM.

Despite their continued use, EFMs are notoriously unreliable and require constant repositioning as the woman or baby move around. It is also possible to confuse the mother’s heart rate with the baby’s. Often they malfunction, causing an alarm to go off for no reason. This can create an atmosphere of panic, adding to the stress of the situation.

Babies’ heart rates do shift significantly during labor. Sometimes they even fall asleep, causing doctors to think that they are distressed.

Studies have shown that when EFMs are used, C-section rates increase. This is partially due to practitioners’ concerns and fear of litigation when there is a shift in the baby’s heart rate. The fact that it is much harder to walk around when an EFM is in use may also contribute to increases in surgery.

If you must use a hospital where EFM is used routinely, try to work out a compromise. Perhaps your doctor will consent to intermittent monitoring with the EFM. Some EFMs use telemetry, which transmits information from the sensors to the box via remote. Since no wires are used, you can move about more easily.

Cesareans
The cesarean, perhaps more than any other major surgical procedure, has enormous life-saving potential. We are fortunate to live in a time when this procedure usually means that both infant and mother will survive.

In theory, a C-section is used to remove a baby from the mother’s womb surgically when, for some reason, a vaginal birth cannot happen or would endanger the life or health of the mother or child.

In practice, however, C-sections are often used before the possibility of vaginal birth has been adequately ruled out.

Let’s look at some scenarios where cesarean surgery is absolutely required:

* Placenta previa. For unknown reason, the placenta sometimes grows partially or completely over the cervical opening. A vaginal birth could tear the placenta, depriving the baby of oxygen and nourishment. It is sometimes possible to deliver vaginally if there is only partial placental previa.
* Prolapsed umbilical cord. When the umbilical cord comes out of the cervical opening before the baby does, there is a danger that the baby’s oxygen supply could be cut off.

The conditions below might require C-section, although surgery may not be necessary depending on the circumstances:

* Active herpes at the time of labor. Sometimes lesions can be covered with bandages, and vaginal delivery is possible.
* Transverse lie. In this condition, the baby is positioned sideways in the mother’s belly.
* Cephalopelvic disproportion. This is when the baby’s head is simply too large to pass through the pelvis. Although physicians often schedule a C-section ahead of time for a baby they believe has cephalopelvic disproportion, the condition is rare, and can only be determined when you are actually in labor.
* Decision to end pregnancy early. This might be done if the baby has a medical condition that can be better treated outside the womb.
* Severe preeclampsia or uncontrolled diabetes.

Unfortunately, most cesareans are performed on women for less certain reasons such as:

* Failure to progress.
* Fetal distress. This does happen to some babies, and surgery can save their lives. Many experts believe this is done too frequently, however, and without good medical cause.
* Breech position. Most infants in the breech position, where the baby comes out legs or buttocks first instead of headfirst, are delivered via C-section automatically. This accounts for about 4 to 5 percent of all C-sections. While there is no evidence that cesarean delivery of breech babies is safer than vaginal birth, it has now become difficult to find practitioners who have been trained in breech delivery.
* Twins. Studies have not shown that automatic delivery of twins via C-section is statistically safer. Vaginal delivery of twins is rapidly turning into another lost art, much like breech delivery.
* Large baby.
* Health problems in the mother. Hypertension, diabetes, and other conditions don’t necessarily require C-sections, but many physicians perform them just to be on what they call the “safe side.”
* Previous cesarean.
* Convenience.

Are Cesareans Safe? It bears repeating: a C-section is a major surgery. Like any other surgical procedure, it involves a number of risks and consequences, both physical and emotional.

During vaginal birth, natural hormones are released that contribute to the well-being of the baby. Some of these, the catecholamines, the so-called fight-or-flight hormones, help the baby to breathe, retain body heat, remain alert, and control pupil dilation to see the mother better. Babies who are born via cesarean miss out on these health benefits, although babies who are born surgically seem to do better if the mother has been in labor prior to the surgery. Babies born via C-section have a much higher incidence of breathing difficulties.

In terms of the mother’s health, current statistics show that the risk of death to the mother from a C-section is 2 to 4 times greater than that of vaginal birth. Contributing factors to maternal death include reactions to anesthesia, infection, and hemorrhage. Many women who have cesarean require rehospitalization for various reasons. Women who have had cesarean sections seem to be at increased risk for ectopic pregnancy, placenta abruptio, and placenta previa in future pregnancies. A recent National Institute of Health (NIH) conference on the topic concluded that women planning to have more than one child need to be aware of the increased risks of these conditions with repeat cesareans.

Also of great importance is the psychological effect that cesarean can have on a woman. One study of women who underwent emergency C-sections showed that 52 percent of them had various forms of post-traumatic stress disorder one to two months after the baby was born. Other women leave their birth experience feeling disappointed, and perhaps even angry with themselves for not being able to have the birth they’d hoped for.

To learn more about the rising rates of cesareans, and some of the cultural reasons behind that increase read Cesarean Birth in a Culture of Fear.

Vaginal Birth after Cesarean (VBAC)
“Once a cesarean, always a cesarean.” The reasons behind this outdated cliché was that a woman who had undergone a previous cesarean section had a scarred, weakened uterus that could more easily rupture during the stress of another labor and delivery.

Fortunately, cesarean surgery has changed and improved over the years. Once upon a time, a woman having a C-section would receive a long vertical scar from her navel to her pubic bone. Now, a cesarean can be performed with a low horizontal cut popularly referred to as a bikini cut, only 3 or 4 inches wide. This type of incision is much more stable for future deliveries.

How safe is a VBAC? The main safety concern of VBAC is the risk of uterine rupture. However, a woman attempting VBAC has a 99.8 percent chance of birthing without a uterine rupture. In addition, most studies show that no woman or baby has ever died from a uterine rupture, no matter what type of incision the woman had. On the other hand, women have died from complications of cesareans, and the death rate is even higher for repeat cesareans.

In any event, the words uterine rupture evoke terrifying images of the uterus tearing in two. In truth, the uterus typically tears slowly, not all at once, and is accompanied by noticeable symptoms. Uterine rupture can happen to any woman in any pregnancy. It can even happen before labor begins, although this is not common.

There are conditions that contraindicate VBAC. If a woman has placenta previa or abruptio placenta, she will need to have an emergency C-section. This is also true if the baby is clearly in distress.

If you are a petite woman, you may be convinced that you can’t handle vaginal birth, especially if you have already had a C-section. There is no evidence to back this up. Small women can give birth to very large babies.

Deciding to have a VBAC. Current statistics show that the success of a VBAC is strongly influenced by environment. The current nationwide rate for VBACs is 24.9 percent. Certified nurse-midwives, however, have a success rate of 68.9 percent overall, and some even have rates as high as 80 or 90 percent.
Trackback URL for this post:
http://www.mothering.com/trackback/3951

No comments:

Post a Comment