Operational Obstetrics & Gynecology
Problems During Labor and Delivery
Most labors occur within 2 weeks of the due date. Labor occurring prior to the 38th week of pregnancy is preterm labor, although definitions vary depending on the clinical circumstances.
While delivering a little bit early usually poses no particular problem for the mother or the baby, more significant amounts of prematurity pose more significant risks for the infant. Of these, immaturity of the respiratory tree is among the most hazardous, but other organs can also be a problem.
The cause of preterm labor is unknown, but in about half the cases, it is associated with detectable intrauterine infection. Another significant number are associated with placental abruption.
Our instincts are to try to prevent preterm delivery to avoid the morbidity associated with it. This instinct is based on the premise that the problem is primarily one of prematurity. If, however, preterm labor in a particular patient is just a symptom of an underlying problem (infection, fetal stress, etc.), then vigorous attempts to prevent delivery, when successful, may only delay treatment of the underlying problem. Further, the medications commonly used to prevent premature delivery have significant side effects and risks. For these reasons, judgment is used to decide who should be treated for preterm labor and who shooed be allowed to deliver. In many civilian hospitals, no attempt is made to arrest labor after the 34th week.
Threatened preterm labor consists of regular, frequent contractions (every 10 minutes) that do not lead to a change in the cervix. In many civilian hospitals, it is customary to withhold any labor-stopping medication until cervical change is noted. These civilian hospitals also have abundant resources to treat preterm labor and premature infants should labor unexpectedly progress rapidly. In an operational setting, such resources may not be available and earlier treatment may be indicated.
In military settings, it is often helpful to postpone delivery long enough to get the patient to a definitive care setting, even if the patient is more than 34 weeks gestation. It is best to coordinate the use of these medications with the receiving facility. Any of the following treatments may effectively disrupt the labor process for 24-48 hours, and this is usually long enough to move the patient to an area of greater resource.
While postponing delivery, many fetuses less than 34 weeks gestation will benefit from administering steroids to the mother. The effect of the steroids on the fetus is to accelerate fetal pulmonary maturity, lessening the risk of respiratory distress syndrome of the newborn. Appropriate doses include:
When transporting the mother to a definitive care setting, have her remain way over on her left or right side, with a pillow between her knees, and an IV securely in place. If IV access is lost during a bumpy truck or helo ride, it will be nearly impossible to restart it without stopping or landing.
Most women will rupture their membranes during labor. If membranes rupture prior to the onset of labor, this is called premature rupture of the membranes, or PROM.
The obstetrical significance of PROM is that labor needs to begin promptly or infection will develop with bacteria ascending through the birth canal. In some cases of PROM, the reason the membranes rupture prematurely is because there is an established infection which has weakened the membranes.
If the pregnancy is at full term and there is no evidence of infection, no treatment is necessary initially, because most women will go into spontaneous labor within the next 6 hours. After 6 hours of rupture, or in the face of infection or other pressing clinical circumstance, labor can be induced. Unless infection is evident, antibiotics are not helpful.
When PROM occurs remote from term, two basic approaches can be taken...induce labor or wait for the fetus to mature further. There are pros and cons to each approach and the decision will hinge on individual clinical circumstances. This decision is best made in consultation with a definitive care facility.
Confirmation of PROM is optimally made via a sterile speculum examination, looking for pooled amniotic fluid in the vagina, Nitrazine positive fluid, ferning positive fluid, and to obtain a culture of the fluid.
A fetus in transverse lie cannot deliver vaginally and requires a cesarean section to avoid uterine rupture during labor. Some of these women will also have a placenta previa (as the cause of the transverse lie). Others will need an urgent cesarean because of prolapsed cord. Without the fetal head or butt occupying the birth canal, it is relatively easy for an umbilical cord to prolapse through a widely dilated cervix with ruptured membranes.
If the fetus and arm are relatively small in comparison to the maternal pelvis, vaginal delivery may still be possible, but with some risk of injury to the arm.
The bones of the fetal scalp are soft and meet at "suture lines."
Over the forehead, where the bones meet, is a gap, called the "anterior fontanel," or "soft spot." This will close as the baby grows during the 1st year of life, but at birth, it is open.
The occiput of the baby has a similar obstetric landmark, the "posterior fontanel."
This junction of suture lines in a Y shape that is very different from the anterior fontanel.
In cases of fetal scalp swelling or significant molding, these landmarks may become obscured, but in most cases, they can identify the fetal head position as it is engaged in the birth canal.
The fetal position is usually described using three letters.
In other words, the fetal occiput is directed towards the mother's left, anterior side.
These anterior presentations are normal and usually are the easiest way for the fetus to traverse the birth canal.
As labor progresses and the fetal head descends, the occiput usually rotates anteriorly, converting this LOT to an LOA or OA as the head delivers.
If the head fails to rotate despite steady descent, this is called a "deep transverse arrest," and is common among:
Women with this condition who fail to deliver spontaneously are treated with cesarean section, forceps, or vacuum extraction, depending on the clinical circumstances, available resources, and experience of the operator.
Prolonged Latent Phase Labor
Women with a prolonged latent phase risk exhaustion and an increased risk of uterine infection (chorioamnionitis).
No single treatment of prolonged latent phase will necessarily be successful in nudging the patient into active phase labor, but each of the following have been successful in many patients:
Normal labor progresses at a rate of no less than 1.2 cm/hour (for first babies) to 1.5 cm/hour (for subsequent babies). If active labor progresses more slowly than this, an "arrest of labor" has occurred.
The arrest of labor may be simple slowing of the labor below the expected rate, or may represent a complete arrest, in which there is no further progress for at least 2 hours.
There are essentially only two causes for an arrest of labor:
Contractions may be inadequate because they are too infrequent (more than 4 minute intervals), or do not last long enough (less than 30 seconds). Often in this situation, they are neither frequent enough nor long enough.
Mechanical impediments to labor may include:
Inadequate contractions are treated with uterine stimulation. This is generally accomplished with intravenous oxytocin, delivered in steady, small amounts with a controlled infusion pump. The dose is started relatively low, and then advanced gradually until the desired effect is achieved. Later in labor, the dosage is often adjusted downward or stopped altogether if the contractions are too close together (consistently more than 5 contractions every 10 minutes).
In an operational setting where a controlled infusion pump is not available, two other options can be employed:
The possibility of a mechanical impediment should be considered whenever arrest disorders occur.
Usually, there is no way to know in advance which labors will experience an absolute obstruction and those that will not. For this reason, a trial of labor is almost always indicated. Those patients with an absolute obstruction will demonstrate a complete arrest pattern and will need cesarean section.
Shoulder dystocia means difficulty with delivery of the fetal shoulders. Although this is more common among women with gestational diabetes and those with very large fetuses, it can occur with babies of any size. Unfortunately, it cannot be predicted or prevented.
After delivery of the head, the fetus seems to try to withdraw back into the birth canal (the "Turtle Sign"). Digital exam reveals that the anterior shoulder is stuck behind the pubic symphysis.
In more severe cases, the posterior shoulder may be stuck at the level of the sacral promontory.
While most of these nerve injuries heal spontaneously and completely, some do not.
A generous episiotomy can be helpful. If a spontaneous laceration has occurred, or if the perineum is very stretchy and offers no obstruction, it is not necessary to also perform an episiotomy.
If this has no effect, do not exert increasing pressure. Instead, try some alternative maneuvers to free the shoulder.
The MacRobert's Maneuver involves flexing the maternal thighs tightly against her abdomen. This can be done by the woman herself or by assistants.
While in the MacRobert's position, gentle downward traction can again be attempted.
Suprapubic pressure can be applied to drive the fetal shoulder downward, clearing the pubic bone.
Sometimes, the suprapubic pressure is more effective if applied in a somewhat lateral direction, rather than straight down.
This tends to nudge the shoulder into a more oblique orientation, which in general provides more room for the shoulder.
Gentle downward traction on the fetal head in combination with this suprapubic pressure may relieve the obstruction.
Often, the posterior arm has entered the hollow of the sacrum. By reaching in posteriorly and sweeping the arm up and out of the birth canal, enough additional space will be freed to allow the anterior shoulder to clear the pubic bone.
This drawing makes the maneuver look easier than it is. Because of limited visibility and space, this maneuver is sometimes difficult or impossible.
Identify the posterior shoulder and follow the fetal humerus down to the elbow. Then you can identify the fetal forearm. Grasping the fetal wrist, draw the arm gently across the chest and then out.
The concept of unscrewing the light bulb can be applied to shoulder dystocia problems.
This model shows the birth attendant pushing the anterior shoulder in a counterclockwise direction. As the baby rotates, the posterior shoulder comes up outside of the subpubic arch. At the same time, the stuck anterior shoulder is brought posteriorly into the hollow of the sacrum. As the rotation continues a full 360 degrees, both shoulders are rotated (unscrewed) out of the birth canal.
Applying fundal pressure in coordination with other maneuvers may, at times, be helpful. Applied alone, it may aggravate the problem by further impacting the shoulder against the symphysis.
Breech babies can present in a variety of ways, including buttocks first, one leg or both legs first.
Frank breech means the buttocks are presenting and the legs are up along the fetal chest. This is the safest position for breech delivery.
If either foot is presenting ("footling breech"), there are increased risks of umbilical cord prolapse and delivery of the feet through an incompletely dilated cervix, leading to arm or head entrapment.
Because of the risks of breech delivery, in many civilian hospitals most or all breech babies are born by cesarean section.
In operational settings, cesarean section may not be available or may be more dangerous than performing a vaginal breech delivery.
The simplest breech delivery is called a spontaneous breech.
The mother pushes the baby out with the normal bearing down efforts and the baby is simply supported until it is completely free of the birth canal. These babies pretty much deliver themselves.
This works best with smaller babies, mothers who have delivered in the past, and frank breech presentation.
If the breech baby gets stuck half-way out, or if there is a need to speed the delivery, an "assisted breech" delivery is performed. For this type of delivery, it is very helpful to have a second person to aid you.
A generous episiotomy will give you more room to work, but may be unnecessary if the vulva is very stretchy and compliant.
A towel can be wrapped around the lower body to give the you a more stable grip.
Have your assistant apply suprapubic pressure to keep the fetal head flexed.
If the arms are trapped in the birth canal, you may need to reach up along the side of the baby and sweep them, one at a time, across the chest and out of the vagina.
It is important to keep you hands low on the baby's hips. If you grasp the baby above the hips, it is relatively easy to cause soft tissue injury to the abdominal organs, including the kidneys.
If you bring the baby's body above the horizontal axis, you risk injuring the baby's spine.
Only when the baby's nose and mouth are visible at the introitus is it wise to bring the body up.
The application of suprapubic pressure by the assistant is important for keeping the head flexed against the chest, expediting delivery, and reducing the risk spinal injury.
At this stage, the baby is still unable to breath and the umbilical cord is likely occluded.
Without rushing, move steadily toward a prompt delivery.
Placing your finger in the baby's mouth may help you control the delivery of the head.
Try not to let the head "pop" out of the birth canal. A slower, controlled delivery is less traumatic.
About 40% of twins present as cephalic/cephalic. The remainder pose some abnormal presentation of one or both twins. Because of the abnormal presentations and the complexities of delivering twins, many are delivered by cesarean section in civilian settings. Some physicians favor cesarean delivery for all twins. In many operational settings, this approach may not be available or wise, and vaginal delivery may be performed.
Following delivery of the first twin, there is a period of time during which contractions slow or stop. Both placentas remain inside the uterus and attached.
It is usually safest to make no attempt to speed up this process, but to await the resumption of contractions. This could take a few minutes or many minutes. While waiting, monitor the second twin's heart beat and if normal, continue to observe the patient.
If contractions do not promptly resume, it is acceptable to stimulate the uterus with oxytocin.
With your hand in the vagina, feel the fetal presenting part. If it is not engaged, try to guide it down to the pelvic inlet. Avoid rupturing membranes until the fetal presenting part is engaged in the birth canal.
As the presenting part descends, ask the mother to bear down and usually the second twin will deliver as easily as the first twin. First twins are usually bigger than their sibling.
This can be a big problem for the fetus if the cord is compressed, blocking the flow of blood to the baby.
Immediate delivery is the best solution to this problem.
If immediate delivery is not available, put the mother in the knee-chest position and use your hand in her vagina to elevate the fetal head back up into the uterus. This action may relieve enough pressure on the umbilical cord that oxygen can still get through to the baby. Transport the mother in the knee-chest position and you with your hand elevating the fetal presenting part to the nearest facility in which immediate delivery is possible.
Umbilical Cord Around the Neck
This is a frequent occurrence during delivery. Nearly half of babies have the umbilical cord wrapped around something (neck, shoulder, arm, etc.), and this generally poses no particular problem for them.
In a few cases, the cord will be wrapped so tightly around the baby's neck (after delivery of the head but before the shoulders are delivered) that you cannot get the rest of the baby out without risk of tearing the umbilical cord.
After delivery of the baby, the placenta will detach from the inside of the uterus and will be expelled, often with additional pushing efforts by the mother. Normally this occurs within a few minutes of delivery of the baby, but may take as long as an hour.
Often after about 30 minutes of waiting, a manual removal of the placenta is undertaken. Anesthesia (regional or general) is typically used for this as manual removal causes a great deal of abdominal cramping. In operational settings, if necessary, it may be performed without anesthesia or with some IV narcotic analgesia.
One hand is inserted through the introitus and into the uterine cavity. Grasp the edge of the placenta and use the side of your hand to sweep the placenta off the uterus. Then pull the placenta through the cervix. Most placentas can be easily and uneventfully removed in this way. A few prove to be problems.
When you manually remove the placenta, be prepared to deal with an abnormally adherent placenta (placenta accreta or placenta percreta). These abnormal attachments may be partial or complete.
Average blood loss following a delivery is about 500 cc. Bleeding that is significantly in excess of that is considered post partum hemorrhage.
Most cases of post partum hemorrhage are caused by the uterus not contracting firmly after delivery. In some cases, there is a retained blood clot inside the uterus which disallows a firm, tight contraction. Manually expressing the blood clot by squeezing the fundus will usually control bleeding from this source.
Uterine massage is an immediate treatment, often very effective, in stopping the bleeding. Oxytocin can be added:
Bimanual compression of the uterus is an effective way of slowing or stopping the bleeding associated with post partum hemorrhage.
The uterus is elevated out of the pelvis by the vaginal hand, and compressed against the back of the pubic bone by the abdominal hand.
Blood transfusion may be life saving in some of these patients.
In a non-pregnant patient, progressive hypovolemia is usually accompanied by the predictable signs of tachycardia, hypotension and tachypnea before confusion and loss of consciousness occur. Women with immediate post partum hemorrhage do not necessarily follow that path and may look surprisingly well until they collapse. Because of this, your decision to give or not give blood to these women should depend heavily on your estimated blood loss, clinical circumstances and likelihood of continuing blood loss, and less on her vital signs. Women who quickly lose half their blood volume (2500 out of 5000 ml) usually benefit from transfusion.
In civilian settings, banked blood is usually given. In many operational settings, banked blood is not available and fresh, whole blood will be used.
Chorioamnionitis is an infection of the placenta and fetal membranes.
In its' earliest stage, there may be no symptoms or clinical signs. As it becomes more advanced, clinical evidence of infection may appear, including:
Chorioamnionitis may be a problem for both the mother and the fetus. Maternal infections can prove to be very serious. The fetus may suffer not just from infection, but also because of the elevated core temperature of the mother. Increased core temperatures lead to an increased metabolic rate of the fetal enzyme systems, which in turn need more oxygen than normal. At times, this increased oxygen demand cannot be met and the fetus may become progressively acidotic.
Chorioamnionitis during labor is usually treated very aggressively, with broad-spectrum, intravenous antibiotics such as:
Maternal temperature is treated with oral or rectal acetaminophen, 1 gm every 4 hours.
Plans are made for prompt delivery.
GBS is a source of significant morbidity and sometimes mortality. Many women are asymptomatic carriers.
A variety of schemes to reduce perinatal GBS infections have been proposed and used in different civilian settings. In operational settings, once good way of dealing with this issue is to treat on the basis of risk factors.
Using this approach, women with any of the following risk factors are treated for possible GBS:
Treatment consists of:
Maternal febrile morbidity is classically defined as temperatures exceeding 100.4 on at least two occasions, at least 6 hours apart.
For patients with an obvious infection with high fever, localizing signs and septic in appearance, treatment is initiated prior to fulfillment of the 6-hour definition.
Cultures from the urine and vagina (and sometimes blood) can be useful in civilian settings. In operational settings, their value may be limited. Similarly, a chest x-ray, which might be ordered and promptly obtained in a civilian setting may not be available or of any practical value in a military setting.
Examine the patient, looking for localizing signs that will guide you in your therapy. Check for:
If a specific source is identified, treatment specific for that source can be employed. However, in operational settings, there is considerable risk of multiple sources and vigorous antibiotic therapy is generally initiated. Good choices for such therapy include:
Home · Introduction · Medical Support of Women in Field Environments · The Prisoner of War Experience · Routine Care · Pap Smears · Human Papilloma Virus · Contraception · Birth Control Pills · Vulvar Disease · Vaginal Discharge · Abnormal Bleeding · Menstrual Problems · Abdominal Pain · Urination Problems · Menopause · Breast Problems · Sexual Assault · Normal Pregnancy · Abnormal Pregnancy · Normal Labor and Delivery · Problems During Labor and Delivery · Care of the Newborn
This web version of Operational Obstetrics & Gynecology is provided by The Brookside Associates Medical Education Division. It contains original contents from the official US Navy NAVMEDPUB 6300-2C, but has been reformatted for web access and includes advertising and links that were not present in the original version. This web version has not been approved by the Department of the Navy or the Department of Defense. The presence of any advertising on these pages does not constitute an endorsement of that product or service by either the Department of Defense or the Brookside Associates. The Brookside Associates is a private organization, not affiliated with the United States Department of Defense. All material in this version is unclassified.
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