Abnormal Labour and it Management

Definitions

Stages and Phases of Normal Labour

Causes of Abnormal Labour

Types of Abnormal Laobur

Diagnosis and Management of Abnormal

Labour

Normal labor refers to the presence of regular uterine contractions that cause progressive dilation

and effacement of the cervix and fetal descent.

Abnormal labor, dystocia, and failure to progress :

Terms used to describe a difficult labor pattern that deviates from that observed in the majority of

women who have spontaneous vaginal deliveries.

This problem is the most common indication for primary cesarean birth, accounting for three times more cesarean

deliveries than malpresentation or fetal heart rate abnormalities

• Second stage: Time from complete cervical dilatation to expulsion of the fetus

• Third stage: Time from expulsion of the fetus to expulsion of the placenta

latent

Active

Acceleration Phase

Maximum slope

Deceleration phase

• First stage:

Time from the onset of labor until complete cervical dilatation

Latent phase

Active phase

Second Stage

ETIOLOGY OF PROTRACTION AND ARREST DISORDERS :

Abnormal labor can be the result of one or more abnormalities:

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 multiparous women is 50 and 20 minutes, respectively.

The upper limit of duration associated with a normal perinatal outcome had been defined as two hours ( but

was subsequently lengthened)

Other factors may affect its duration: Epidural analgesia, duration of the first stage, parity,

maternal size, birth weight, and station at complete dilation.

THE SECOND STAGE

The normal duration of 2nd stage of labor should be based upon parity and presence of regional anesthesia, with no intervention as long as the fetal heart

rate pattern is normal and some degree of progress is observed.

Sacral Promon

tory

Vaginal examination to determine the diagonal conjugate

Symphysis 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 in mmHg measured by an internal monitor multiplied by their frequency per 10 minutes)

90 % of women in spontaneous active labor achieved contractile activity > 200 Montevideo units (in 40 % reaches 300 units).

Normal uterine activity

• Protraction disorders: refer to slower-than-normal labor progress.

• Arrest disorders: refer to complete cessation of progress.

Protraction and arrest disorders may occur in both the first and second stage of labor

It is important to emphasize that the rates of cervical change listed in Table 1 are two 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 or arrest disorders in the first stage of labor was 13 percent [12], second stage abnormalities appeared to be as common [6].

latent phase: begins as short, mild, irregular uterine contractions that soften, efface, and begin to dilate the cervix (< 1 cm/h).

Active phase: starts at 3 to 5 cm dilation cervical dilation accelerate to at least 1 to 2 cm/ h (various depending on parity) per hour and the fetus descends into the birth canal ends when the cervix is fully dilated

The total duration of labor also varies between nulliparous and parous parturients. One report of 25,000 women at term revealed the average duration of active labor (onset defined as 3 cm dilation) in nulliparous and parous women was 6.4 and 4.6 hours, respectively

Latent Phase

The average duration of latent phase in nulliparous and multiparous women is 6.4 and 4.8 hours

An abnormally long latent phase is defined as 20 hours for the nullipara and 14 hours for the multiparous woman .Occur in 4-6%

Prolonged latent phase is responsible for 30 % abnormalities in nulliparas and over 50 % of abnormalities in multiparous women

begins as short, mild, irregular uterine contractions that soften, efface, and begin to dilate the cervix

Risks Of Prolonged Latent Phase:

Mothers: Higher risk of cesarean delivery (due to maternal exhaustion) and longer hospital stay .

The newborns: Higher rate of perinatal morbidity but not mortality

- are more likely to require neonatal intensive 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 onset of 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 a protraction or arrest disorder in the active phase of labor.

Women with prolonged latent phase are not more prone to developing subsequent protraction and arrest disorders than parturients with a normal latent phase

MANAGEMENT OPTIONS OF A PROLONGED LATENT PHASE:

Therapeutic rest

Oxytocin

Amniotomy

Cervical ripening

It refers to uterine activity that is either not sufficiently strong or not appropriately coordinated to dilate the cervix and expel the fetus.

Is the most common cause of protraction or arrest disorders in the first stage of labor.

It occurs in 3 to 8 percent of parturients and can be quantified as uterine contraction pressures less than 200 Montevideo 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 active phase.

• Absolute: true disparity between fetal and maternal pelvic dimensions.

• Relative: due to fetal malposition (e.g., extended or asynclitic fetal head) or malpresentation (mentum posterior, brow), rather than a.

Causes of Dystocia

Dystocia due to malposition:5 % of cephalic presenting fetuses experience malposition with persistent occiput posterior (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 hours once active labor is diagnosed to determine whether progression is

adequate)

The use of partogram

APPROACH TO THE PATIENT WITH ABNORMAL LABOR

• Amniotomy • Oxytocin for treatment of Hypo contractile uterine activity Low 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 of a women's response to a particular dose is not possible

Options f management include

Diagnosis:

When There Is No Progress (Protraction Disorder Persists) Despite Oxytocin Therapy To Achieve > Or = 200 Montevideo Units For Greater Than Two Hours.

Active Phase Arrest

Treatment:

Cesarean Delivery Is Typically Performed At This Point

Continued observation.

Attempt at operative vaginal delivery.

Cesarean delivery.

Dystocia in the second stage

Risk factors include: nulliparity, diabetes, macrosomia, epidural anesthesia, oxytocin usage, and chorioamnionitis

Observation: Most women with a prolonged 2nd stage ultimately deliver vaginally.

Suggested noninvasive interventions:

- changes in maternal position. - continuous emotional support of the parturient - delaying pushing if the fetal head is high in the pelvis at full 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 the mother and fetus.

success is dependent upon the training and skill of the obstetrician.

Risks: - Longer second stage.- higher incidence of operative delivery.- larger episiotomies.- more severe perineal lacerations.

Occiput posterior position

A small increase in second stage length in the presence of a reassuring fetal heart rate, favorable clinical assessment of fetal relative to maternal size, and progress in 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 figure 3). The key points are listed below:

• Monitor progress in active labor with cervical exams at 1 to 2 hour intervals.

• If the patient in active labor fails to progress adequately for two hours, then intact membranes should be ruptured and oxytocin administered to achieve uterine contractions greater than 200 Montevideo units. These patients can be observed for two to four hours as long as clinical assessment of fetal and maternal size is favorable and the fetal heart rate is reassuring.

• The decision to perform an operative vaginal delivery (eg, extraction or rotation) in the second stage versus continued observation or cesarean birth is based upon clinical assessment of mother and fetus and the skill and training of the obstetrician.