COMPLICATIONSWITH THEPOWER(THE FORCE OF THELABOR)UNIVERSITY OF NORTHERN PHILIPPINESGRADUATE SCHOOLMASTER OF ARTS IN NURSING
A.INEFFECTIVE UTERINE FORCE Uterine contractions are the basic force moving thefetus through the birth canal. Contractions occur because of interplay ofenzymes, electrolytes, proteins and hormones. About 95% of labors are completed withcontractions that follow a predictable, normalcourse. When they become abnormal or ineffective,ineffective labor occurs.
Hypotonic ContractionsHypertonic ContractionsUncoordinated ContractionsTHE CAUSES OF INEFFECTIVE UTERINE FORCEDEPEND ON THE 3 TYPES OF DYSFUNCTION:
HYPOTONIC CONTRACTIONS Number of contractions:not more 2 or 3 occurring in a 10-minuteperiod. Resting tone: less than 10 mm Hg Strength of contractions: does not riseabove 25 mm Hg. Phase of Labor: Active Symptom: Painless
ETIOLOGY: Overstretching of the uterus – large baby,multiple babies, polyhydramnios, multiparity. Bowel or bladder distention, preventingdescent. Excessive use of analgesia.
HYPERTONIC CONTRACTIONS Resting tone: more than 15 mm Hg. Contractions: Frequent prolonged contractions thatare not productive. Phase of Labor: Latent Symptom: Painful Cause: This type of contraction occurs because themuscle fibers of the myometrium do not repolarize orrelax after a contraction, thereby “wiping it clean” toaccept a new pacemaker stimulus.
COMPLICATION: FETAL ANOXIA Management: Provide comfort measures Bedrest or position changes Hydration Mild sedation Tocolytics Caesarean delivery
Uncoordinated Contractions With uncoordinated contractions, more than onepacemaker may be initiating contractions, orreceptor points in the myometrium may be actingindependently of the pacemaker. Uncoordinated contractions may occur so closelytogether that they do not allow good cotyledon (oneof the visible segments on the maternal surface ofthe placenta) filling.
Uncoordinated Contractions cont’d Applying a fetal and a uterine external monitor andassessing the rate, pattern, resting tone, and fetalresponse to contractions for at least 15 minutes (orlonger if necessary in early labor) reveals theabnormal pattern. Oxytocin administration may be helpful inuncoordinated labor to stimulate a more effectiveand consistent pattern of contractions with a better,lower resting tone.
B. DYSFUNCTIONAL LABOR AND ASSOCIATEDSTAGES OF LABORDysfunction at the First Stage of LaborProlonged Latent Phase When contractions become ineffective during the firststage of labor, a prolonged latent phase can develop. A prolonged latent phase is a latent phase that is longerthan 20 hours in a nullipara or 14 hours in a multipara. This may occur if the cervix is not “ripe” at the beginningof labor and time must be spent getting truly ready forlabor. It may occur if there is excessive use of ananalgesic early in labor.
Prolonged Latent Phase cont’d With a prolonged latent phase, the uterus tends to be in ahypertonic state. Relaxation between contractions is inadequate,and the contractions are only mild (less than 15 mm Hg) andtherefore ineffective. One segment of the uterus may be contracting with more forcethan another segment. Management of a prolonged latent phase in labor that has beencaused by hypertonic contractions involves helping the uterus torest, providing adequate fluid for hydration, and pain relief with adrug such as morphine sulfate. Changing the linen and the woman’s gown, darkening roomlights, and decreasing noise and stimulation can also be helpful. These measures usually combine to allow labor to becomeeffective and begin to progress. If it does not, a cesarean birth oramniotomy (artificial rupture of membranes) and oxytocininfusion to assist labor may be necessary.
Protracted Active Phase A protracted active phase is usually associated withcephalopelvic disproportion (CPD) or fetal malposition,although it may reflect ineffective myometrial activity. This phase is prolonged if cervical dilatation does not occur ata rate of at least 1.2 cm/hr in a nullipara or 1.5 cm/hr in amultipara, or if the active phase lasts longer than 12 hours in aprimigravida or 6 hours in a multigravida. If the cause of the delay in dilatation is fetal malposition orCPD, cesarean birth may be necessary. Dysfunctional labor during the dilatational division of labortends to be hypotonic, in contrast to the hypertonic action atthe beginning of labor. After an ultrasound to show that CPD is not present, oxytocinmay be prescribed to augment labor.
Prolonged Deceleration Phase A deceleration phase has become prolonged whenit extends beyond 3 hours in a nullipara or 1 hour ina multipara. Prolonged deceleration phase most often resultsfrom abnormal fetal head position. A cesarean birthis frequently required.Secondary Arrest of Dilatation A secondary arrest of dilatation has occurred ifthere is no progress in cervical dilatation for longerthan 2 hours. Again, cesarean birth may benecessary.
DYSFUNCTION AT THE FIRST STAGE OF LABORProlonged Descent Prolonged descent of the fetus occurs if the rate ofdescent is less than 1.0 cm/hr in a nullipara or 2.0cm/hr in a multipara. It can be suspected if thesecond stage lasts over 3 hours in a multipara. With both a prolonged active phase of dilatationand prolonged descent, contractions have been ofgood quality and proper duration, and effacementand beginning dilatation have occurred, but thenthe contractions become infrequent and of poorquality and dilatation stops.
Prolonged Descent cont’d If everything is normal except for the suddenlyfaulty contractions and CPD and poor fetalpresentation have been ruled out byultrasound, then rest and fluid intake, as advocatedfor hypertonic contractions, also apply. If the membranes have not ruptured, rupturing themat this point may be helpful. Intravenous (IV) oxytocin may be used to inducethe uterus to contract. A semi-Fowler’s position, squatting, kneeling, ormore effective pushing may speed descent.
Arrest of Descent Arrest of descent results when no descent hasoccurred for 1 hour in a multipara or 2 hours in anullipara. Failure of descent has occurred when expecteddescent of the fetus does not begin or engagementor movement beyond 0 station has not occurred. The most likely cause for arrest of descent duringthe second stage is CPD. Cesarean birth usually isnecessary. If there is no contraindication to vaginal birth,oxytocin may be used to assist labor.
C. PATHOLOGIC RETRACTION A contraction ring is a hard band that forms across theuterus at the junction of the upper and lower uterinesegments and interferes with fetal descent. The most frequent type seen is termed a pathologicretraction ring (Bandl’s ring). The ring usually appearsduring the second stage of labor and can be palpatedas a horizontal indentation across the abdomen. It is a warning sign that severe dysfunctional labor isoccurring as it is formed by excessive retraction of theupper uterine segment; the uterine myometrium ismuch thicker above than below the ring.
C. PATHOLOGIC RETRACTION cont’d When a pathologic retraction ring occurs in earlylabor, it is usually caused by uncoordinatedcontractions. In the pelvic division of labor, it is usually caused byobstetric manipulation or by the administration ofoxytocin. In either event, the fetus is gripped by the retractionring and cannot advance beyond that point. Theundelivered placenta will also be held at that point. Contraction rings often can be identified byultrasound. Such a finding is extremely serious andshould be reported promptly.
C. PATHOLOGIC RETRACTION cont’d Administration of IV morphine sulfate or the inhalation ofamyl nitrite may relieve a retraction ring. A tocolytic canalso be administered to halt contractions. If the situation is not relieved, uterine rupture andneurologic damage to the fetus may occur. In the placental stage, massive maternal hemorrhagemay result, because the placenta is loosened but thencannot deliver, preventing the uterus from contracting. Most likely, a cesarean birth will be necessary to ensuresafe birth of the fetus. Manual removal of the placenta under generalanesthesia may be required if the retraction ring doesnot allow the placenta to be delivered.
FIGURE (A) NORMAL SHAPE OF PREGNANT ABDOMEN DURING LABOUR, IN AWOMAN LYING ON HER BACK; (B) BANDL’S RING IN THE ABDOMEN OF AWOMAN WITH OBSTRUCTED LABOUR.
D. PRECIPITATE LABOR Precipitate labor and birth occur when uterinecontractions are so strong that a woman gives birth withonly a few, rapidly occurring contractions. It is often defined as a labor that is completed in fewerthan 3 hours. Precipitate dilatation is cervical dilatation that occurs ata rate of 5 cm or more per hour in a primipara or 10 cmor more per hour in a multipara. Such rapid labor is likely to occur with grandmultiparity, or it may occur after induction of labor byoxytocin or amniotomy.
D. PRECIPITATE LABOR cont’d Contractions can be so forceful that they lead topremature separation of the placenta, placing thewoman at risk for hemorrhage. Rapid labor also poses a risk to the fetus, becausesubdural hemorrhage may result from the rapid releaseof pressure on the head. A woman may sustain lacerations of the birth canal fromthe forceful birth. She also can feel overwhelmed by thespeed of labor. A precipitate labor can be predicted from a labor graphif, during the active phase of dilatation, the rate isgreater than 5 cm/hr (1 cm every 12 minutes) in anullipara or 10 cm/hr (1 cm every 6 minutes) in amultipara.
D. PRECIPITATE LABOR cont’d In such instances, a tocolytic may be administered toreduce the force and frequency of contractions. Caution a multiparous woman by week 28 of pregnancythat, because a past labor was so brief, her labor thistime also may be brief. This allows her to plan forappropriately timed transportation to the hospital oralternative birthing center. Both grand multiparas and women with histories ofprecipitate labor should have the birthing roomconverted to birth readiness before full dilatation isobtained. Then, even a sudden birth can beaccomplished in a controlled surrounding.
E. UTERINE RUPTURE Uterine rupture occurs when a uterus undergoes morestrain than it is capable of sustaining. Rupture occurs most commonly when a vertical scarfrom a previous cesarean birth or hysterotomy repairtears. Contributing factors may include prolonged labor,abnormal presentation, multiple gestation, unwise use ofoxytocin, obstructed labor, and traumatic maneuvers offorceps or traction. When uterine rupture occurs, fetal death will followunless immediate cesarean birth can be accomplished. If a uterus should rupture, the woman experiences asudden, severe pain during a strong labor contraction,which she may report as a “tearing” sensation.
E. UTERINE RUPTURE cont’d Rupture can be complete, going through theendometrium, myometrium, and peritoneum layers, orincomplete, leaving the peritoneum intact. With acomplete rupture, uterine contractions will immediatelystop. Two distinct swellings will be visible on the woman’sabdomen: the retracted uterus and the extrauterinefetus. Hemorrhage from the torn uterine arteries floods into theabdominal cavity and possibly into the vagina. Signs of shock begin, including rapid, weak pulse; fallingblood pressure; cold and clammy skin; and dilatation ofthe nostrils from air hunger. Fetal heart sounds fade and then are absent.
E. UTERINE RUPTURE cont’d If the rupture is incomplete, the signs of rupture are lessevident. With an incomplete rupture, a woman mayexperience only a localized tenderness and a persistentaching pain over the area of the lower uterine segment. However, fetal heart sounds, a lack of contractions, andthe changes in the woman’s vital signs will graduallyreveal fetal and maternal distress. Uterine rupture can be confirmed by ultrasound. Administer emergency fluid replacement therapy asordered.
E. UTERINE RUPTURE cont’d Anticipate use of IV oxytocin to attempt to contract theuterus and minimize bleeding. Prepare the woman for a possible laparotomy as anemergency measure to control bleeding and achieve arepair. The viability of the fetus depends on the extent of therupture and the time elapsed between rupture andabdominal extraction. A woman’s prognosis depends on the extent of therupture and the blood loss. Most women are advised not to conceive again after arupture of the uterus, unless the rupture occurred in theinactive lower segment.
F. INVERSION OF THE UTERUS Uterine inversion refers to the uterus turning inside outwith either birth of the fetus or delivery of the placenta. It may occur if traction is applied to the umbilical cord toremove the placenta or if pressure is applied to theuterine fundus when the uterus is not contracted. It may also occur if the placenta is attached at thefundus so that, during birth, the passage of the fetuspulls the fundus down. Inversion occurs in various degrees. The invertedfundus may lie within the uterine cavity or the vagina, or,in total inversion, it may protrude from the vagina.
F. INVERSION OF THE UTERUS cont’d When an inversion occurs, a large amount of bloodsuddenly gushes from the vagina. The fundus is notpalpable in the abdomen. If the loss of blood continues unchecked for longer thana few minutes, the woman will show signs of blood loss:hypotension, dizziness, paleness, or diaphoresis. Because the uterus is not contracted in thisposition, bleeding continues, and exsanguination couldoccur within a period as short as 10 minutes. Never attempt to replace an inversion, because handlingof the uterus may increase the bleeding. Never attempt to remove the placenta if it is stillattached, because this only create a larger surface areafor bleeding.
F. INVERSION OF THE UTERUS cont’d In addition, administration of an oxytocic drug onlycompounds the inversion or makes the uterus moretense and difficult to replace. An IV fluid line needs to be started, if one is not alreadypresent (use a large-gauge needle, because blood willneed to be replaced). If a line is already in place, open it to achieve optimalflow of fluid to restore fluid volume. Administer oxygen by mask, and assess vital signs. Be prepared to perform cardiopulmonary resuscitation(CPR) if the woman’s heart should fail from the suddenblood loss.
F. INVERSION OF THE UTERUS cont’d The woman will immediately be given generalanesthesia or possibly nitroglycerin or a tocolytic drugintravenously, to relax the uterus. The physician or nurse-midwife then replaces thefundus manually. Administration of oxytocin after manual replacementhelps the uterus to contract and remain in its naturalplace. Because the uterine endometrium was exposed, awoman will need antibiotic therapy to prevent infection. She needs to be informed that cesarean birth willprobably be necessary in any future pregnancy, toprevent the possibility of repeat inversion.
G. AMNIOTIC FLUID EMBOLISM Amniotic fluid embolism occurs when amniotic fluid isforced into an open maternal uterine blood sinusthrough some defect in the membranes or aftermembrane rupture or partial premature separation ofthe placenta. Previously, it was thought that particles such asmeconium or shed fetal skin cells in the amniotic fluidentered the maternal circulation and reached thelungs as small emboli. Now, it is recognized that a humoral or anaphylactoidresponse is the more likely cause. This condition may occur during labor or in thepostpartal period.
G. AMNIOTIC FLUID EMBOLISM cont’d It is not preventable because it cannot be predicted. Possible risk factors include oxytocinadministration, abruptio placentae, and hydramnios. The clinical picture is dramatic. A woman, in stronglabor, sits up suddenly and grasps her chest becauseof sharp pain and inability to breathe as sheexperiences pulmonary artery constriction. Shebecomes pale and then turns the typical bluish grayassociated with pulmonary embolism and lack ofblood flow to the lungs. The immediate management is oxygen administrationby face mask or cannula.
G. AMNIOTIC FLUID EMBOLISM cont’d Within minutes, she will need CPR. CPR may beineffective, however, because these procedures(inflating the lungs and massaging the heart) do notrelieve the pulmonary constriction. Therefore, bloodstill cannot circulate to the lungs. Death may occurwithin minutes. A woman’s prognosis depends on the size of theembolism, the speed with which the emergencycondition was detected, and the skill and speed ofemergency interventions. Even if the woman survives the initial insult, the riskfor disseminated intravascular coagulation (DIC) ishigh, further compounding her condition.
G. AMNIOTIC FLUID EMBOLISM cont’d In this event, she will need continued managementthat includes endotracheal intubation to maintainpulmonary function and therapy with fibrinogen tocounteract DIC. Most likely, she will be transferred to an ICU. The prognosis for the fetus is guarded, becausereduced placental perfusion results from the severedrop in maternal blood pressure. Labor often begins or the fetus is born immediately bycesarean birth.
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