Abnormal Labour and it Management Definitions Stages and Phases of Normal Labour Causes of Abnormal Labour Types of Abnormal Laobur Diagnosis and Management of AbnormalLabour
Normal labor refers to the presence of regularuterine contractions that cause progressive dilationand effacement of the cervix and fetal descent.Abnormal labor, dystocia, and failure toprogress :Terms used to describe a difficult labor pattern thatdeviates from that observed in the majority ofwomen who have spontaneous vaginal deliveries.This problem is the most common indication for primarycesarean birth, accounting for three times more cesareandeliveries than malpresentation or fetal heart rateabnormalities
• Second stage:Time from complete cervical dilatation to expulsion of the fetus• Third stage:Time from expulsion of the fetus to expulsion of the placentalatentActiveAcceleration PhaseMaximum slopeDeceleration phase• First stage:Time from the onset of labor until complete cervical dilatation
ETIOLOGY OF PROTRACTION AND ARRESTDISORDERS :Abnormal labor can be the result of one or moreabnormalities:o The cervix.o The uterus.o The maternal pelvis.o The Fetus (i.e., power, passenger, or pelvis).
The median duration varies in nulliparous and multiparouswomen is 50 and 20 minutes, respectively.The upper limit of duration associated with a normalperinatal outcome had been defined as two hours ( butwas subsequently lengthened)Other factors may affect its duration:Epidural analgesia, duration of the first stage, parity,maternal size, birth weight, and station at completedilation.THE SECOND STAGEThe normal duration of 2ndstage of labor should be based upon parity andpresence of regional anesthesia, with no intervention as long as the fetal heartrate pattern is normal and some degree of progress is observed.
SacralPromontoryVaginal examination to determine the diagonal conjugateSymphysis Pubis
Quantitatives Assessment:- Palpation.- External tocodynamometry.- Internal uterine pressure catheters.95 % of women in labor will have 3-5 contractions per 10 minutes.Quantifying assessment:The Montevideo units (i.e., the peak strength of contractions inmmHg measured by an internal monitor multiplied by their frequencyper 10 minutes)90 % of women in spontaneous active labor achieved contractileactivity > 200 Montevideo units (in 40 % reaches 300 units).Normal uterine activity
• Protraction disorders: refer to slower-than-normallabor progress.• Arrest disorders: refer to complete cessation ofprogress.Protraction and arrest disorders may occur in both the first and second stage oflaborIt is important to emphasize that the rates of cervical change listed in Table 1 aretwo standard deviations from the mean and thereby used to define abnormal;they do not represent the mean or median rates.CLASSIFICATION – Of Labor Abnormalities:
INCIDENCE – In one large series, the incidence or protraction orarrest disorders in the first stage of labor was 13 percent , secondstage abnormalities appeared to be as common .
latent phase: begins as short, mild, irregular uterinecontractions that soften, efface, and begin to dilate the cervix(< 1 cm/h).Active phase: starts at 3 to 5 cm dilation cervical dilationaccelerate to at least 1 to 2 cm/ h (various depending onparity) per hour and the fetus descends into the birth canalends when the cervix is fully dilatedThe total duration of labor also varies between nulliparousand parous parturients. One report of 25,000 women atterm revealed the average duration of active labor (onsetdefined as 3 cm dilation) in nulliparous and parous womenwas 6.4 and 4.6 hours, respectively
Latent PhaseThe average duration of latent phase in nulliparous and multiparouswomen is 6.4 and 4.8 hoursAn abnormally long latent phase is defined as 20 hours for the nulliparaand 14 hours for the multiparous woman .Occur in 4-6%Prolonged latent phase is responsible for 30 % abnormalities in nulliparasand over 50 % of abnormalities in multiparous womenbegins as short, mild, irregular uterine contractions that soften, efface, andbegin to dilate the cervix
Risks Of Prolonged Latent Phase:Mothers: Higher risk of cesarean delivery (dueto maternal exhaustion) and longer hospital stay.The newborns: Higher rate of perinatal morbiditybut not mortality- are more likely to require neonatalintensive care unit admission.- have meconium at birth.- have depressed Apgar Score.
CONTRIBUTING FACTORS to Prong longed Latent Phase:• The State of the Cervix: Women with more favorable cervices at the onsetof labor have a shorter latent phase.• Sedation and analgesia/anesthesia may slow the latent phase:PROGNOSIS :The diagnosis of prolonged latent phase must not be confused with aprotraction or arrest disorder in the active phase of labor.Women with prolonged latent phase are not more prone to developingsubsequent protraction and arrest disorders than parturients with a normallatent phase
MANAGEMENT OPTIONS OF A PROLONGEDLATENT PHASE:Therapeutic restOxytocinAmniotomyCervical ripening
It refers to uterine activity that is either not sufficientlystrong or not appropriately coordinated to dilate thecervix and expel the fetus. Is the most common cause of protraction or arrestdisorders in the first stage of labor. It occurs in 3 to 8 percent of parturients and can bequantified as uterine contraction pressures less than 200Montevideo units.Hypocontractile uterine activity
Role of Epidural analgesia:Dystocia due to cephalopelvic disproportion (Relative or Absolute) :• This diagnosis is currently based upon slow or arrested labor during the activephase.• Absolute: true disparity between fetal and maternal pelvic dimensions.• Relative: due to fetal malposition (e.g., extended or asynclitic fetal head) ormalpresentation (mentum posterior, brow), rather than a.Causes of DystociaDystocia due to malposition:5 % of cephalic presenting fetuses experience malposition with persistent occiputposterior (OP) position or transverse arrest.
Prevention: by proper management of labor: The diagnosis of labor. Monitoring of labor progress. assessment of maternal and fetal well-being.(Women should undergo cervical examination every one to two hoursonce active labor is diagnosed to determine whether progression isadequate) The use of partogramAPPROACH TO THE PATIENT WITH ABNORMAL LABOR
•Amniotomy• Oxytocin for treatment of Hypo contractile uterine activityLow dose regimens: (to avoid uterine hyperstimulation)High dose regimens: (shorten labor )Management of Dystocia in the first stage:Oxytocin is typically infused to titrate dose to effect, as prediction ofa womens response to a particular dose is not possibleOptions f management include
Diagnosis:When There Is No Progress (Protraction DisorderPersists) Despite Oxytocin Therapy To Achieve > Or =200 Montevideo Units For Greater Than Two Hours.Active Phase ArrestTreatment:Cesarean Delivery Is Typically Performed At This Point
Continued observation. Attempt at operative vaginal delivery. Cesarean delivery.Dystocia in the second stageRisk factors include:nulliparity, diabetes, macrosomia, epidural anesthesia,oxytocin usage, and chorioamnionitis
Observation:Most women with a prolonged 2nd stage ultimately delivervaginally.Suggested noninvasive interventions:- changes in maternal position.- continuous emotional support of the parturient- delaying pushing if the fetal head is high in the pelvis atfull dilatation and the woman has no urge to do so- active management using high dose oxytocin.Operative vaginal delivery :The choice of instrument require careful assessment of themother and fetus.success is dependent upon the training and skill of theobstetrician.
Risks:- Longer second stage.- higher incidence of operative delivery.- larger episiotomies.- more severe perineal lacerations.Occiput posterior positionA small increase in second stage length in the presence of a reassuring fetal heartrate, favorable clinical assessment of fetal relative to maternal size, and progressin the second stage does not mandate rotation or operative delivery.Management of OP: Operative Delivery From OP Position. Manual Or Instrumental Rotation To Occiput Anterior. Cesarean Delivery.
RECOMMENDATIONS:A general labor management algorithm is outlined in Figure 3 (show figure3). The key points are listed below:• Monitor progress in active labor with cervical exams at 1 to 2 hourintervals.•If the patient in active labor fails to progress adequately for two hours,then intact membranes should be ruptured and oxytocin administered toachieve uterine contractions greater than 200 Montevideo units. Thesepatients can be observed for two to four hours as long as clinicalassessment of fetal and maternal size is favorable and the fetal heart rate isreassuring.•The decision to perform an operative vaginal delivery (eg, extraction orrotation) in the second stage versus continued observation or cesarean birthis based upon clinical assessment of mother and fetus and the skill andtraining of the obstetrician.