PATHOLOGY
OF LABOR AND PUERPERIUM
Dystocia
Dystocia (difficult labor) may be defined as cessation of progress in parturition.
The causes fall into three main groups:
I. Uterine forces that are not strong enough to overcome the natural resistance offered to the birth of the baby by the birth canal. Weakness of uterine action is called uterine inertia and is the most common cause of dystocia.
2. Faulty presentation or abnormal development of the fetus.
3. Abnormalities in the size or the character of
the birth canal that form an obstacle to fetal
descent.
Dysfunctional Labor
"Hypocontractility" in which uterine contractions
occur less than twice per 10 minutes and average less than 25 mmHg is the
most common cause of dysfunctional labor. Progress in labor is arrested
or retarded in terms of rate of cervical effacement and dilatation and
descent and rotation of the presenting part. Abnormal cervical compliance
(cervix remains firm and poorly effaced) has been implicated as the underlying
cause in a small percentages of cases (approximately 3%). Patients with
arrested labor must be evaluated for obstruction of the birth canal, fetal
origin, placental origin, or, if in the second stage, poor patient effort.
(which may be an effect of heavy analgesia). Dysfunctional labor may also
present in the form of "hypercontractility," which is manifested
by more than five contractions in 10 minutes with or without elevated resting
pressures (normal range of 8 to 12 mmHg). This abnormal uterine behavior
may occur with placental abruption, and in some preeclamptic parturients.
Precipitate Labor
Fetal welfare is compromized when the intensity of uterine contractions
is increased, intervals are shortened, and duration is increased. A combination
of excessively forceful uterine contractions and minimal soft tissue resistance
can give rise to precipitate labor, fetal anoxia and cerebral trauma, maternal
lacerations, and postpartal hemorrhage caused by uterine atony. Early recognition
of the problem, timely preparation for delivery under controlled conditions,
and properly administered analgesia or anesthesia may minimize these risks.
Uterine Constriction Rings
In association with ineffectual uterine contractions, there may be annular,
spastic muscular strictures that do not rise or change position as labor
advances. Unlike the pathologic retraction ring of Bandle, they are not
associated with obstructed labor and they cannot be palpated externally
at the junction of the lower and upper uterine segments.
The majority are palpable only on the uterine interior. Often, they arise
from inappropriate manual or oxytocic stimulation. Relaxants including
amyl nitrite, intravenous epinephrine, ~r deep anesthesia may eliminate
the localized myometrial spasms, but more often abdominal delivery is required.
Intrapartal
Infection
Normally, there appear to be natural defenses in the mother that are effective
in preventing intrapartal infections. Obviously, host resistance in general
is affected by the overall health status; the cervical mucous plug, intact
membranes and perhaps antibacterial activity in the amniotic fluid are
also important factors. These defense mechanisms are lost when the membranes
rupture. Within 48 hours the great majority of patients will have positive
amniotic fluid cultures, The longer the duration of membrane rupture prior
to delivery the higher the incidence of "chorioamnionitis,'' and,
in some cases, a rapid invasion of gram-negative bacilli will produce septic
shock. Thus, an accurate diagnosis of ruptured membranes is crucial. Usually,
by observation or inspection or utilizing the nitrazine paper test (positive
results due to alkaline amniotic fluid), fern test (amniotic fluid allowed
to dry shows ferning)l and cytologic examination (presence of vernix caseosa
cells) the diagnosis can be established. Serial (usually daily) ultrasonic
examinations for amniotic fluid index and biophysical profile are utilized
to determine if chorioamnionitis has occurred.
Treatment is predicated on many variables; however, once chorioamnionitis
develops, the fetus and the mother are at risk. Thus, it is recommended
that regardless of gestational age the fetus with chorioamnionitis should
be delivered. Often, there is a dilemma because immaturity of the fetus
at the time of membrane rupture may mean the chances of extrauterine survival
would not be great. This is of particular urgency in those of less than
27 weeks of gestation. With parental involvement the decision is often
made for conservative therapy. In such cases this watchful waiting will
offer the only chance of fetal survival but is all too frequently unsuccessful.
In one recent series there were no survivors with rupture below 25 weeks.
In those below 28 weeks there was a nearly 60~c risk of chorioamnionitis,
and 50% perinatal mortality, and only 30% of the survivors were neurologically
normal at 6 months.
Unfortunately, prophylactic antibiotics do not protect the mother or the
fetus. Tocolytic agents are generally contraindicated in the presence of
ruptured membranes. A delay of some 18 to 24 hours after rupture of the
membranes tends to provoke fetal lung maturity and lessen the likelihood
of the respiratory distress syndrome. Within 48 hours of administering
B-methasone therapy to the mother, even greater lung maturation can be
achieved in the fetus. This seems particularly useful from 27 to 32 weeks
of gestation. Thus, if there is no evidence of infection in the mother
and the gestation is more than 26 weeks' and less than 34 weeks' duration,
corticosteroid therapy and expectancy until pulmonary maturity might be
an appropriate management.
Bed rest is continued as long as there is active leakage. It is advisable
to use external electronic fetal monitoring for some time after admission
to evaluate the possibility of fetal tachycardia (distress) from occult
cord prolapse. After an initial sterile speculum examination, no others
are made.
About 8% of these patients will go into labor spontaneously within 72 hours.
Despite the risk of provoking a Candida albicans infection in the infant,
antibiotic coverage during labor may reduce the likelihood of puerperal
morbidity.
Once pulmonary maturity is assured, there is little to be gained by waiting.
Thus. in an asymptomatic woman whose gestation is 35 weeks or more or with
evidence of overt signs of infection at earlier stages, the presence of
documented ruptured membranes may indicate induction of labor or, should
this be contraindicated or unsuccessful, abdominal intervention. The appropriate
cultures for mixed bacteria are taken initially after the diagnosis of
membrane rupture is. established. At any time amnionitis is detected (temperature
above 99" F in the morning, white blood count above 12,000, fetal
tachycardia above 160) delivery should be accomplished within 8 hours.
Broad-spectrum antibiotics are given by infusion in labor.
Pelvic Contraction
The common types of pelvic contraction may be classified in four main groups:
contraction of the inlet; contraction of the midpelvis; contraction of
the outlet; and combinations of inlet. midpelvic, and outlet contraction.
Inlet contraction is defined as diminution of the obstetric conjugate measurement
(by roentgenogram) to 10.0 cm or less or diminution of the diagonal conjugate
measurement (clinical) to 11.5 cm or less. When the interischial spinous
diameter is 9.5 cm or less (by roentgenogram), there is transverse contraction
of the midpelvis. In outlet contraction the angle formed by the pubic rami
is narrow, and the ischial tuberosities are close together; thus, it resembles
a male pelvis insofar as the outlet is concerned. Often it is called a
funnel pelvis. It is customary to make a diagnosis of outlet contraction
whenever the intertuberous distance is 8 cm or less by clinical measurement
or 10 cm or less by roentgenographic measurement.
The sum of the interischial tuberous diameter (TI) and the posterior sagittal
diameter of the outlet (PSO) should be 15.0 cm or more by clinical measurement
to be considered normal.
It should be noted that the size of the pelvis is only one important factor
in determining whether or not a given fetus can be delivered through a
given pelvis. Other factors involved in the eventual outcome include size
of the fetus, moldability of the fetal head, fetal position and presentation,
rigidity of the maternal soft parts, the uterine powers, and other clinical
features. Clinical examination of the pelvis in context with an appreciation
of these several factors as the mechanism and course of labor is observed
provides adequate information to manage most patients successfully without
resort to the use of x-ray pelvimetry, which has potential fetal hazards.
A notable exception is the anticipated vaginal delivery of a breech presentation
when x-ray pelvimetry may be mandatory. Ultrasound studies may assist in
evaluating untoward problems involving the fetus. An oxytocin infusion
in a carefully titrated administration is advisable only in patients in
whom disproportion has been ruled out.
If the infusion administered, a lack of progressive cervical dilation,
or descent of the fetal head suggests an inadequate pelvis. A deceleration
phase of more than 3 hours in primigravidas or I hour in multiparas is
abnormal. A diagnosis of arrest of descent in the second stage is made
by finding no progress over an hour's time.
Pelvic Dystocia
The treatment of dystocia due to abnormal pelvis varies with the degree
of contraction, the size of the infant and, in multiparas, the history
of previous labors. Successful treatment depends on the ability to determine
the extent of disproportion between the infant and the pelvis. However.
in general, a normally developed full-term infant cannot be born spontaneously
and alive when the true conjugate measures 10 cm or less. However, in modern
obstetrics, fetal monitoring is instituted and the decision for intervening
at an optimal time may be based more on the fetal status and clinical situation
than any arbitrary set of pelvic measurements. Certainly. if the trial
of labor is continued until there is a pathologic retraction ring of Bandle,
indicative of an obstructed labor, the possibility of very serious fetal
jeopardy already exists.
Dystocia due to abnormalities in the fetus include (I) excessive size,
(2) fetal anomalies, (3) hydrocephalus, (4) multiple pregnancies. and (5)
transverse lie. In "shoulder, oblique, or breech presentations,"
when placenta previa has been excluded, external cephalic version may be
carefully attempted before or early in labor, provided that the patient's
parity is not great, the fetal membranes are intact, and the presenting
part is not markedly engaged. If this fails, then cesarean section is necessary
except in the breech for vaginal delivery group. Any patient with a documented
contracted pelvis should be subjected to cesarean section. The grave risk
of uterine rupture with internal manipulations has made the procedure obsolete.
Rarely, spontaneous evolution of a transverse lie may occur-either by Douglas'
or Denman's method in which a small macerated fetus may be expelled spontaneously,
or delivery may occur by a mechanism in which the fetus is doubled upon
itself (conduplicato corpore).
Posterior
Occipital Position
The majority of occiput posterior (OP) positions are delivered ultimately
in the anterior position. However, at the onset of labor, posterior position
of the occiput is a common finding. Persistent occiput posterior includes
those cases that do not rotate anteriorly (only about 5%).
In the vast majority of OP positions, anterior rotation takes place spontaneously
if patience is exercised. In a very small minority (and only after the
cervix is fully dilated) one of the following procedures may be necessary:
(1) manual rotation of the head to OA, followed by application of forceps
(2) forceps rotation to OA followed by reapplication of forceps (Scanzoni
maneuver); and (3) delivery with forceps as a posterior. If the fetal head
is considerably molded or the pelvis is anthropoid or android in type or
shows midpelvic contraction, delivery by forceps as an occiput posterior
may prove to be the least traumatic to the mother and the fetus, but each
case must be considered and treated individually. However, since OP presentations
enhance perinatal morbidity and mortality electronic fetal monitoring or
fetal blood scalp sampling should be used to ascertain fetal well-being
until these definitative therapies may be applied.
Breech Presentation
Breech presentations are classified as follows:
I. Complete, when the feet and the legs are flexed on the thighs, and the
thighs are flexed on the abdomen, so that the buttocks and the feet present
2. Incomplete, when the foot or the knee, in any combination, presents
through the cervix
3. Frank, when the legs are extended and lie against the abdomen and the
chest, and the buttocks present The diagnosis of breech presentation depends
on palpating the hard ballotable head in the fundus with the irregular
soft breech above the symphysis.
Rectal or vaginal examination reveals the characteristic parts. The fetal
heart sounds are heard through the back of the fetus at about the level
of the umbilicus. The normal mechanism includes (I) engagement and (2)
descent, ordinarily in one of the oblique diameters. Usually it is the
anterior hip that first encounters the resistance of the pelvic floor,
causing an internal rotation of 45 degrees that brings the anterior hip
to the pubic arch. If the posterior hip descends first, internal rotation
occurs through an arc of 135 degrees. Descent continues until the perineum
is distended, when the posterior hip is delivered over the anterior margin
of the perineum by lateral flexion of the body, followed by the spontaneous
delivery of the legs and the feet. As the shoulders reach the perineum
they undergo internal rotation to the anteroposterior diameter. The flexed
head enters the pelvis in one of the oblique diameters and then rotates
so that the posterior neck engages under the symphysis. The head is born
in a position of flexion, with the chin, the mouth, the nose, the forehead,
the bregma and the occiput appearing in succession over the perineum.
The relatively high perinatal mortality (approximately 15%) of breech presentation
is due mainly to the increased incidence of prematurity fetal anomalies,
complications of gestation and labor, the presentation itself being responsible
for only about one third of the deaths, trauma and anoxia accounting for
many of these. Prolapse of the umbilical cord is a particular hazard of
the complete and incomplete varieties, the incidence being, respectively,
about 12 and 22 times the usual incidence for vertex presentation (0.5%).
In the latter weeks of pregnancy, substitution of a vertex presentation
may be attempted by external version. (See subsequent section devoted to
this subject.)
Vaginal breech deliveries may be of three types: I. A spontaneous delivery
is one in which the entire infant is expelled by natural forces.
2. A partial breech extraction is one in which the infant is extruded as
far as the umbilicus by natural forces, but the remainder of the body is
extracted by the attendant. This method of delivery is the one of choice
whenever feasible.
3. A total breech extraction is one in which the entire body of the infant
is extracted by the attendant. This method should rarely be necessary.
Ideally, the breech should be allowed to advance spontaneously until the
umbilicus has been born.
The completion of labor is facilitated if the arms remain crossed on the
chest and the head is sharply flexed. This is best obtained by avoiding
traction and by moderate downward pressure on the fundus as soon as the
breech begins to emerge through the vulva.
When delivery by traction is necessary, the traction on the legs and the
body should be downward until an axilla becomes visible, when the body
is flexed upward, delivering the posterior shoulder over the perineum.
By depressing the body of the fetus the anterior shoulder is brought to
emerge beneath the pubic arch. The head usually occupies an oblique diameter
with the chin posteriorly and is best delivered by Mauriceau's maneuver.
The index finger of one hand is introduced into the mouth of the child
and applied over the superior maxilla, while the body rests upon the palm
of the hand.
Two fingers of the other hand are then hooked over the neck and, grasping
the shoulders, make down ward traction until the occiput appears over the
symphysis. The body is now extended upward, and the mouth the brow, the
nose, and the occiput emerge successfully over the perineum. Piper forceps
to the aftercoming head are favored by many obstetricians.
Current management is predicated upon the findings that vaginal delivery
is risky and that, in general, perinatal mortality and morbidity can be
improved by utilizing abdominal delivery more freely than in the past.
The vulnerable groups include complete and incomplete (footling) breeches,
among whom the incidence of prolapsed cord may be 10%, patients with premature
labor or who have an in utero growth retardation problem (12%-14%) and
primigravidas with average to large term-sized fetus. The trend now is
to require specific indications and justification for vaginal delivery
in breech presentations. The general contraindications to vaginal birth
after previous cesarean are previous classical incision, macrosomic fetus,
fetal malposition, and multiple pregnancy. Many authorities also indicate
that the initial cause for the cesarean should be nonrecurrent, that there
be no more than one previous cesarean, and that the postoperative course
after the first was uncomplicated.
Generally, current criteria for vaginal delivery in the breech presentation
include only frank breech presentation, a gestational age of 34 weeks or
more, an estimated fetal weight of 2,000 g to 3,500 g, a flexed fetal head,
an adequate maternal pelvis as determined by x-ray pelvimetry, and no maternal
or fetal indications for cesarean section. Obviously, other circumstances
may also be suitable, but are less ideal, for example, a previable fetus
(<25 weeks of gestation), documented lethal congenital anomalies, and
presentation so far in the delivery process that vaginal delivery is safer
than attempting cesarean.
Recently, considerable attention has been directed to attempting to prevent
the breech presentation in labor by performing external version in the
third trimester. Although still mildly controversial, it now appears that
even if tocolytics are necessary, external version may be accomplished
with relative safety and that there is risk-benefit justification on the
basis of decreasing the incidence of breech presentations at term.
Face Presentation
Since face presentations result from extension of the fetal head, the characteristic
sign is that the cephalic prominence is palpable on the same side as the
back instead of on the small parts as in vertex presentation. The heart
sounds are heard on the side of the small parts and are louder than usual.
Delivery occurs by (I) descent, as in vertex presentation, with internal
rotation and flexion; (2) extension; and (3) external rotation.
If the pelvis is normal and the chin anterior, spontaneous delivery or
an easy forceps delivery should be anticipated, no treatment being necessary.
Internal rotation brings the chin under the symphysis, the head being delivered
by flexion, with the nose, the eyes, the brow, the bregma, and the occiput
appearing in succession over the anterior margin of the perineum. After
the birth of the head the occiput sags backward and undergoes external
rotation to the side toward which it was originally directed. The face
must rotate, because delivery of a mature baby with the chin posterior
is impossible. The initial position of the chin is posterior in about 3%
of these cases.
Anterior rotation usually occurs spontaneously, though very late. When
this is not the case (about one instance in ten), conversion into a vertex
presentation may be attempted, provided that the face is not deeply engaged,
the pelvis is normal, and the membranes are intact or recently ruptured.
However, usually when the chin remains posterior, cesarean section is preferable.
Finally, if the baby is dead, craniotomy may be necessary.
When a brow presentation is detected at the superior strait, it should
be left alone until it promises to be persistent because the transient
varieties will be born spontaneously as either a vertex or a face presentation.
On the other hand, less than one half of the persistent cases-often attended
by a true disproportion-can be expected to deliver uneventfully; thus,
attempts at conversion or (usually) cesarean section are indicated on a
basis similar to that outlined for face presentations.
Cesarean sections are advocated much more frequently in all cases of malposition
and malpresentation of the fetus and when labor becomes abnormal or fetal
distress develops.
Prolapse
of the Cord
Cord prolapse is most common in conditions that interfere with engagement
at the superior strait; hence, it is most common in transverse and foot
presentations and less often found in frank breech.
The overall incidence is 0.8% of deliveries. Variable deceleration noted
in the fetal heart pattern identified through electronic fetal monitoring
may help identify cord compression in occult prolapses. Persistent fetal
tachycardia, noted on external electronic monitoring immediately or soon
after spontaneous rupture of the membranes, may also signify the existence
of an occult cord prolapse. The cord may sometimes be seen or, provided
that the fetus is alive, may be palpated as a cord with distinct pulsations.
Hypotension in the fetus for any reason may cause the cord to become limp
and possibly prolapse. Perinatal mortality rates of 3% for all cases when
the cord is visible can be anticipated, since many of these infants are
premature.
If the cord prolapses after the cervix has become fully dilated, forceps
are indicated only if the fetus can be delivered quickly and atraumatically.
If the cervix is only partially dilated, the patient should be placed immediately
in the knee-chest position, and by sterile vaginal manipulation an attempt
made to replace the cord. The attempt is frequently unsuccessful, in which
case the presenting part is pushed upward (to decrease pressure on the
cord) and held there until cesarean can be performed. The chances for the
child are poor without cesarean section, but this should not be attempted
unless the fetal heart and the umbilical pulsations are strong after release
of pressure from the cord. Oxygen should be administered to the mother.
It is advisable to perform a sterile vaginal examination and to palpate
for the cord when the diagnosis of abnormal presentation is first made.
Close watch of the FHR is also imperative .
Rupture
of the Uterus
Rupture of the uterus occurs once in approximately every 2,000 cases and
is a grave accident, carrying a composite maternal mortality of about 10%
to 15% and a perinatal mortality of about 50010 to 75%.
There are two main types, spontaneous and traumatic, and each of these,
in turn, may be classified according to whether it occurs in pregnancy
or in labor. Ruptures that occur spontaneously may further be categorized
into three groups:
(l)those with a previous cesarean section scar,
(2) those with previous operative scars, and
(3) those with an intact uterus. The distinction is important because the
maternal mortality rate for ruptures of intact uteri is between 20% and
40%, while that associated with rupture of a cesarean section scar is less
than 5%. It is customary to distinguish between 'complete" and "incomplete"
rupture, according to whether the laceration communicates with the abdominal
cavity or is separated from it by peritoneal covering (subperitoneal hematoma).
Causes.
Currently, spontaneous rupture of the uterus during labor is more common
than traumatic rupture. In the past. nearly one half of the traumatic ruptures
resulted from version and extraction. Other cases resulted from a Braxton
Hicks version, difficult or unsuccessful forceps breech extraction, and
the use of bags and bougies. The common antecedent factors in spontaneous
rupture of the uterus are advanced maternal age and parity, contraction
of the pelvis, a large fetus, and such obvious dystocial factors as abnormal
presentation and impacted pelvic tumors. Excessive stretching of the lower
uterine segment with the development of a pathologic retraction ring plays
an important predisposing role. Pitocin stimulation of the uterus remains
a significant factor in uterine rupture. Other predisposing factors in
the spontaneous rupture of the intact uterus are congenital defects of
the uterus, adenomyosis and a history of previous curettage, manual removal
of the placenta and postabortive or postpartal sepsis. However. with the
increasing incidence of cesarean section, rupture of the scar has become
the most common cause of uterine rupture. The risk of uterine rupture following
a previous cesarean section is about 2%
When the old scar merely disrupts and the myometrium is not freshly lacerated,
the event is more properly referred to as a wound dehiscence than actual
rupture, and the prognosis is much better.
The overall incidence of uterine rupture is approximately the same following
classic and low cervical operations; however, about one third of classic
scars rupture in the later months of pregnancy and are apt to be complete
and dramatic and to occur without warning, while the low cervical ruptures
occur almost exclusively during labor and the signs and symptoms are insidious.
A hematoma may develop within the broad ligament with few or no signs appearing
until the patient begins to have pain and fever during the puerperium.
Symptoms.
Rupture occurring in the later months of pregnancy usually causes sudden,
sharp abdominal pains followed by collapse, but in some cases the immediate
symptoms are mild. If rupture occurs at the time of labor, the patient
usually complains at the height of a uterine contraction of a sharp shooting
pain in the lower abdomen, followed by sudden relief. There may be external
hemorrhage, cessation of uterine contractions, and sudden disappearance
of the fetal heart beat. The lower uterine segment becomes more sensitive
to pressure, the presenting part slips away from the inlet.
and the firmly contracted uterus may be alongside the fetus. The symptoms
of shock from hemorrhage are usually sudden and severe but may be delayed,
especially if the rupture is in the lower uterine segment. Blood may appear
in the urine.
If rupture occurs, immediate laparotomy is necessary. Hysterectomy is usually
required, as is blood transfusion.
Postpartal
Hemorrhage
Serious bleeding following the birth of the child is usually due to (I)uterine
atony, (2) placental retention, (3) deep tears of the birth canal, or (4)
a coagulation defect. In the latter category it is wise to consider von
Willebrand's disease, which is the most common cause of coagulopathy in
women.
Nevertheless, the most common of all causes is uterine atony, which is
responsible for over 90~ of these cases. Among the other causes of postpartal
hemorrhage, the most common are lacerations of the birth canal, operative
delivery, deep anesthesia with agents that relax the uterus (e.g., halothane),
and prolonged labor with maternal exhaustion.
Postpartal hemorrhage should be anticipated and prepared for when any of
these complications present or when there has been overstretching of the
uterus, as in cases of an excessively large fetus, multiple gestation,
hydramnios, or uterine tumors.
Postpartal hemorrhage is defined as bleeding from the birth canal in excess
of 500 ml during the first 24 hours after birth. Postpartal hemorrhage,
as defined, is observed in about 10~ of all deliveries.
In uterine atony there is a continuous flow, which may be very copious,
and the uterus does not exhibit proper contraction. When due to retained
placental tissue the blood may escape in gushes and frequently in large
clots. If the bleeding commences immediately after delivery (third-stage
bleeding), it may be due to tears or to partial separation of the placenta.
If the hemorrhage (usually bright-red blood) continues after the uterus
has been emptied and is well contracted, tears of the cervix, vagina, and
perineum should be looked for and sutured at once. On the other hand, if
the uterus does not contract, the hemorrhage may be due to atony or the
retention of a placental cotyledon, which will be suggested by careful
examination of the fetal surface of the placenta and confirmed by careful
uterine exploration. In the presence of marked bleeding before separation
of the placenta has occurred, manual removal of the placenta should be
carried out at once, certainly before appreciable blood loss has taken
place. Also, if the placenta is retained for more than 30 minutes in the
"absence" of bleeding, the placenta should be removed prophylactically,
Recently there has been a trend toward even earlier manual removal if the
placenta does not separate soon after delivery. On many services it is
routine to explore the uterus after delivery of the placenta to assure
complete evacuation as well as the intactness of the uterus. Certainly,
it is advisable to explore the uterus if there is a question of incompleteness
of placental removal. when bleeding continues after the placenta is expressed
or following a difficult delivery when the uterine wall may have been injured.
Attempts to deliver the placenta by squeezing and kneading the uterus through
the abdomen, as entailed in the original Credé procedure, are not
only futile, but as a rule also traumatize the myometrium and often aggravate
the difficulties. When the placenta has been removed and bleeding continues,
10 U oxytocin (Pitocin), given intravenously slowly and followed by a solution
of 1,000 ml Ringer's lactate with 20 U oxytocin should control the bleeding.
If this fails. and there is no preexisting maternal preeclampsia or hypertension.
0.2 mg ergonovine (Methergine) may be given intramuscularly. If bleeding
persists despite bimanual compression and massage of the uterus, prostaglandin
F2, uterine injections or prostaglandin E suppositories will assist in
uterine contraction and do not have the hypertensive effect of the ergot
preparations. If symptoms of shock appear, the usual treatment of adequate
blood replacement is indicated. Uterine packing has lost favor as a means
of controlling hemorrhage, except as a temporary procedure in rare instances
when hysterectomy is contemplated.
Delivery
by Forceps
The most frequent indications for delivery by forceps are conditions in
which it is desirable to spare the mother second-stage effort, in dysfunctional
labor in the second stage, and in certain situations of fetal distress.
Although to forestall prolonged pressure of the fetal head against a more
or less rigid perineum and to spare the mother the strain of the last few
minutes of the second stage, the use of so-called elective low forceps
has become popular in recent years, particularly in primigravidas .
In general, it is considered good practice, in the absence of disproportion,
to apply forceps if advance is not made after I hour if the head is on
the perineum or is in a position for 'apply forceps," although each
case must be individualized. It should be recognized that even in the second
stage of labor, oxytocic stimulation. further delay or even abdominal intervention
may be choices that are to be preferred to a difficult forceps delivery.
The suggested time limits are appropriate points to evaluate the patient
thoroughly but not necessarily to effect delivery in every case. The difficulty
to be counteracted by the forceps operation and its inherent dangers to
the mother and the fetus must be weighed against the hazards of allowing
a protracted second stage with its significant fetal risks.
The following conditions must be fulfilled before forceps are applied:
I. The child must present correctly, either a vertex or mentum anterior.
2. The cervix must be fully dilated.
3. Membranes must be ruptured.
4. There must be no marked disproportion between the head and the pelvis.
5. The head must have descended to the level of the ischial spines or below.
6. The bladder must be emptied by catheterization.
The most important function of forceps is traction, although they are frequently
employed to rotate the fetal head. Forceps operations are classified according
to the level of the fetal head at the time that the blades are applied:
I. Low forceps-the application of forceps when the head is visible, the
skull is on the perineal floor, and the sagittal suture is in the anteroposterior
diameter of the pelvis.
2. Mid forceps-the application of forceps before the criteria of low forceps
(as stated above) have been met but after engagement has taken place; that
is, after the plane of the greatest cephalic diameter (biparietal) has
passed the inlet. Every effort must be made to avoid this type of potentially
hazardous vaginal delivery in the interests of perinatal welfare.
3. High forceps-the application of forceps before engagement has taken
place. This variety of forceps delivery has no place in modern obstetrics.
For general use the ordinary Simpson forceps are very servicable, but the
particular forceps employed should be varied to suit the particular case.
In certain midforceps extractions, axis traction is essential (Tarnier,
Irving), and in certain cases of transverse arrest, the Kielland forceps
have certain advantages. The Piper forceps generally are employed to deliver
the aftercoming head in breech deliveries. In modern obstetrics, most clinical
situations requiring major forceps operations are best handled by cesarean
section. Occasionally, there may be an indication for the use of a vacuum
extractor as a substitute for forceps when pelvic space is limited.
Version
Version consists of turning the baby in the uterus from an undesirable
into a desirable position. There are three types of version: external,
internal, and Braxton Hicks. According to whether the head or the breech
is made the presenting part, the operation is spoken of as cephalic or
podalic version, respectively. Today, cephalic version has been abandoned.
External version is an operation designed to change a breech or a transverse
presentation into a vertex presentation by external manipulation of the
fetus through the abdominal and the uterine walls.
It is likely to be most successful when done about a month before full
term. Recently, improved success rates have been reported using tocolytics.
Both ultrasonic evaluation and NSTs have been advocated before and after
the procedure. In rare circumstances, the placenta is partially separated,
the uterine integrity is jeopardized, or the cord is entangled or knotted.
The chance of success is greatest if the presenting part is unengaged and
the membranes are intact. In the interest of reducing the relatively high
incidence of cesarean sections, there has been some renewed interest in
this procedure under carefully controlled circumstances. The rewards are
high if successful.
internal version is accomplished with cervical dilation complete. The whole
hand of the operator is introduced high into the uterus and one or both
feet are grasped and pulled downward in the direction of the birth canal.
With his or her other hand (on the abdomen), the obstetrician may expedite
the turning by pushing the head upward. However, the hazard of uterine
rupture and the guarded fetal prognosis have led to the restriction of-this
procedure largely to delivery of a compromised second twin. The use of
Braxton Nicks, version-compressing the lower uterine segment with the infant's
buttocks in placenta previa or stretching the cervix with the infant's
thigh so that labor may be initiated-has no place in modern therapy.
Cesarean
Section.
There are four main types of abdominal cesarean section: (1) classic, (2)
low cervical, (3) extraperitoneal, and (4) cesarean hysterectomy. Low cervical
is further subdivided into vertical and transverse and is the type favored
generally, although other types are preferred in special circumstances.
Accepted indications for cesarean section include a serious disproportion
between the size of the fetal head and the maternal pelvis or fetal malposition.
In certain cases of contracted pelvis. the operation may be indicated if
the trial of labor is unsatisfactory. A history of previous difficult labors
is significant. Other important indications for cesarean section, in descending
order of importance, are hemorrhagic complications (placenta previa, abruptio
placentae), toxemias and intercurrent disease (especially diabetes), and
fetal distress. There are other miscellaneous indications, such as certain
cases of uterine inertia, pregnancy following major vaginal repairs, and
carcinoma of the cervix. Generally, perinatal risks are weighed very high
and when the welfare of the fetus or mother is potentially compromised
by waiting, or if fetal monitoring shows the potential or actual distress
in response to provoked or spontaneous myometrial activity, abdominal intervention
may be desirable.
Except in the presence of an absolute pelvic indication, severe abruptio
placentae or central placenta previa, cesarean section should not be performed
when the child is dead or the mother is in poor condition. The maternal
and the fetal morbidity and mortality are least if cesarean section is
performed before the onset of labor; they increase progressively with the
time the membranes have been ruptured and the duration of labor before
the time of surgery. However, the modern chemotherapeutic agents have added
a considerable margin of safety and flexibility to the use of cesarean
section.
Low cervical cesarean section, plus antibiotic therapy, has been used with
good results in many infected cases. In these circumstances some clinicians
employ an extraperitoneal technique.
The more liberal use of cesarean section in recent years (range of 25%
to 3051~) has unquestionably resulted in greater perinatal salvage; however,
wider use of cesarean section should not be regarded as the ultimate solution
for all antenatal problems. Surgical intervention undoubtedly introduces
maternal risks (e.g., anesthetic, hematologic, and infectious). Objective
tests should be utilized in assessing fetal lung maturity when intervening.
It should be borne in mind, also, that if this mode of delivery is to yield
satisfactory results, it must be selected as a proper and timely technique
of definitive management, not as a last resort after all others fail or
after the fetus has sustained irreversible brain injury. Overall, there
has been a recent trend toward reducing the rising trend for abdominal
intervention .
Puerperal
Infection
Puerperal infection, one of the three major causes of maternal death, is
a postpartal wound infection of the parturient canal (usually of the endometrium)
that may remain localized but often extends along lymphatic and vascular
channels to produce systemic signs and symptoms. Puerperal infections are
grouped under the general term puerperal morbidity, defined as a temperature
of 100.4" F (38.0" C) occurring on two occasions, more than 6
hours apart, exclusive of the first 24 hours. In general, the most common
cause of puerperal infection is the anaerobic Streptococcus, but the hemolytic
Streptococcus is the most common cause of fulminating puerperal infection,
as well as epidemics of the disease. Mixed infections are the rule, and
other organisms include various staphylococci, Escherichia coli, gonococci,
Proteus vulgaris, Enterobacter, Peptostreptococcus, Bacteroides, pneumococci,
and clostridiae. Clostridium perfringens is an uncommon cause of puerperal
infection, but has a dramatic course and high mortality. It is seen more
commonly after criminal abortions than after deliveries near term. Gonorrheal
puerperal endometritis, once considered the cause of 5% to IO% of all fevers
occurring in the puerperium, is rarely seen today. The incidence of puerperal
infection following vaginal delivery should not exceed 3%, although this
figure may reach 25~ or more in patients delivered by cesarean section.
The most important predisposing causes of puerperal infection are hemorrhage
and trauma at the time of labor. Preexisting anemia, undernutrition, and
other debilitated states make puerperal infection more likely. Retention
of placental tissue is a common predisposing factor to infection.
The most common manifestation of puerperal infection is endometritis. Endometritis
usually begins suddenly on the 3rd or the 4th day of the puerperium, with
malaise, headache, chilliness or a chill and temperature of 103" F
or more that remains elevated. The uterus may be enlarged and tender to
pressure. The lochial discharge is variable, relating to the different
organisms responsible for the infection.
If the infection is limited to the uterus, the patient slowly returns to
normal. Rise in temperature indicates an extension, which may lead to abscess
within the broad ligament, the posterior cul-de-sac or the anterior pelvis.
The infection may extend through the uterine lymphatics to cause peritonitis,
or pyemia may develop with typical spiking temperature or, rarely, septicemia
with very rapid death.
Thrombosis may arise in the pelvic veins and extend to the femoral, causing
phlegmasia alba dolens (milk leg). Rarely, ovarian vein thrombosis may
occur with its accompanying inflammation and give rise to protracted fever,
pain, and disability. The most common organisms causing the septic type
are streptococci and staphlococci. Other bacteria causing the condition
are the colon bacillus, Pseudomonas aeruginosa and various anaerobes. Endotoxic
shock following these latter infections carries a grave prognosis.
Prophylaxis.
Most important are (I) maintenance of strict asepsis, (2) restriction of
vaginal and rectal examinations, (3) omission of coitus and vaginal douches
late in pregnancy, (4) prevention of anemia. (5) immediate repair of lacerations,
(6) complete evacuation of placental tissue from the uterus at the time
of delivery, (7) complete evacuation of placental tissue from the uterus
at the time of deliveries, (8) supporting the patient's hydration, (9)
proper bladder care, (10) proper postpartal perineal care, and (II) isolation
of infected patients to protect others.
Since the advent of chemotherapy, adequate blood replacement, improved
prenatal care, and modern techniques of management, fulminating cases of
puerperal infection are rarely encountered.
Treatment.
The type, intensity, and duration of specific therapy will depend upon
the organism involved. drug sensitivities by in vitro tests, the extent
of the infection and the presence of complicating clinical conditions (p.~.,
septic shock, septicemia, thromboembolic disease). Appropriate cultures
should be taken. The procedure of obtaining an intrauterine culture may,
of itself, be beneficial because it promotes drainage. Oxytocins and, if
necessary, ergot preparations may promote uterine drainage. Collections
of pus in the perineum, vagina or cul-de-sac will require adequate drainage.
Transfusions are needed to correct significant anemia. In the more serious
cases, monitoring fluid administrations, electrolyte replacement, urinary
output, and fluid losses and invasive monitoring will be necessary if the
patient is to be supported properly.
Clinical suspicion of lower limb and pelvic thrombophlebitis will call
for diagnostic tests, for example, Doppler ultrasonic flow detector or,
occasionally, the more accurate but invasive method of ascending contrast
phlebography. The presence of thrombophlebitis requires bed rest, use of
anticoagulants, and antibiotics. Initially, heparin infusion is necessary,
but oral warfarin may be begun in 36 to 72 hours, and the heparin discontinued.
If there is femoral phlebitis accompanied by pain and fever, the involved
extremity should be protected and alternating pressure devices utilized
along with elevation until the acute process disappears. After that elastic
support is needed (often for many months) to promote venous drainage.
When there is evidence of parametritis and pelvic cellulitis, it may be
desirable to perform ultrasonic examinations to detect a cul-de-sac abscess
because this must be drained to promote optimal recovery from the infection.
Drainage or uterine debridement by curettage may be called for in endotoxic
shock, which is treated according to the principles outlined for septic
abortions. Otherwise, a curettage might be dangerous and generally it is
best to avoid deep entry of disinfectant solutions or objects into the
vagina. Manipulations should be avoided except for culture taking and checking
on possible lacerations, hematomas, or collections of pus. Hematomas that
are quite large. symptomatic, and continuing to expand should be incised
and drained. There may be a combination of old blood and pus when the diagnosis
is delayed a number of days. Occasionally, morbidity may be associated
with a hematoma above the pelvic fascia, where the blood is paravaginal
or spread into the broad ligament. Retroperitoneal extensions may give
rise to an inguinaj ligament presentation or to rupture into the peritoneal
cavity. Any suspicion of hematoma in the form of unexplained pelvic pain,
feverl tachycardia, hypotension, or anemia must be immediately investigated.
Puerperal infections may be delayed or refractory, characterized by persistent
uterine red or purulent discharge (lochia). There may be continued bleeding
with intermittent passage of old clots.
There are usually pelvic complaints or backaches associated with subinvolution
of the uterus and a low-grade endometritis. The underlying cause may be
retained placental fragments or occasionally, an infected leiomyoma of
the uterus.
Endometritis does not always respond sensitively to antibiotics, particularly
if cervical drainage is poor. While waiting for the antibiotic sensitivity
report, a drug may be chosen on the basis of a Gram-stained smear of the
cervical discharge. Recent hospital antibiotic sensitivity patterns can
be taken into account in the selection of a drug, and it should be given
in adequate doses intravenously.
Mixed infections involving two or more organisms are common, and effective
therapy may require a combination of drugs. Anaerobes frequently participate
in mixed infections; their growth is promoted as secondary invaders into
tissues that have become necrotic after initial infection by facultative
pathogens. The appearance of anaerobic infections may be quite delayed
after an apparent initial successful management. Details of management
of pelvic inflammatory disease are discussed in the section on gynecology.
The types of therapy in mixed pelvic infection (postpregnancy or not) are
similar.
The majority of offending organisms are sensitive to ampicillin or to a
combination of ampicillin and gentamycin given intravenously. Most of the
anaerobes are susceptible t~ ampicillin, penicillin, and the cephalosporins.
The presence of Bacteroides fragilis calls for the use of clindamycin or
chloramphenicol. Massive doses of antibiotics (penicillin, ampicillin,
or erythromycin) are used along with a hyperbaric oxygen chamber and subsequent
surgical intervention in the presence of gas gangrene (Clostridium perfringens)
infection. The possibility of Neisseria gonorrhoeae infections in the vaginal
tract should be considered in screening patients for pathogens. The uncomplicated
case is treated with oral probenecid (1.0 g) followed by intramuscular
injections, at two sites, of aqueous procaine penicillin G (total of 4.8
million units).
