Abnormal labour Abnormal labour

ObjectivesObjectivesAt the completion of this presentation, the participant At the completion of this presentation, the participant should knowshould know::

11 – – Definition of abnormal labour and its causesDefinition of abnormal labour and its causes..

22 – – Abnormalities of the various stages( first and second) Abnormalities of the various stages( first and second) and phases of labour ( latent and active phase)and phases of labour ( latent and active phase)..

33 – – Uterine dysfunction and its various types (hypertonic, Uterine dysfunction and its various types (hypertonic, hypotonic ,ect)hypotonic ,ect)

44 – – What is cephalopelvic disproportion(CPD)What is cephalopelvic disproportion(CPD)..

55 – – Risk factors for poor progress in labourRisk factors for poor progress in labour..

66 – – Dystocia due to pelvic contraction(inlet midpelvis and Dystocia due to pelvic contraction(inlet midpelvis and outlet)outlet)..

77 – – Various methods of estimation of pelvic capacityVarious methods of estimation of pelvic capacity..

88 – – Fetal and maternal effect of abnormal labourFetal and maternal effect of abnormal labour..

Labour become abnormal when there is poor progress Labour become abnormal when there is poor progress ( as evidenced by a delay in cervical dilatation or ( as evidenced by a delay in cervical dilatation or descent of The presenting part, and / or the fetus shows descent of The presenting part, and / or the fetus shows signs of compromise ,similarly by definition, if there is signs of compromise ,similarly by definition, if there is malpresentation ,a uterine scar ,or if labour has been malpresentation ,a uterine scar ,or if labour has been induced , can not be considered normal. induced , can not be considered normal.

DystociaDystocia Dystocia : Literally , difficult labour. Charecterized by Dystocia : Literally , difficult labour. Charecterized by

abnormally slow progress of labour.abnormally slow progress of labour.

Causes : Causes : 4 distinct abnormalities that may exist singly or 4 distinct abnormalities that may exist singly or in combination.in combination.

1 1 –– Abnormalities of the expulsive forces either uterine Abnormalities of the expulsive forces either uterine force insufficiently strong or inappropriately force insufficiently strong or inappropriately coordinated to efface or dilate the cervix. ( Uterine coordinated to efface or dilate the cervix. ( Uterine dysfunction ) , or inadequate voluntary muscle effort dysfunction ) , or inadequate voluntary muscle effort during the second stage of labour.during the second stage of labour.

2 2 –– Abnormalities of presentation, position, or Abnormalities of presentation, position, or development of the fetus.development of the fetus.

3 3 –– Abnormalities of the maternal boney pelvis i.e Abnormalities of the maternal boney pelvis i.e pelvic contraction.pelvic contraction.

4 4 –– Abnormalities of birth canal other than the boney Abnormalities of birth canal other than the boney pelvis that form an obstacle to fetal descend. pelvis that form an obstacle to fetal descend.

Uterine dysfunction is common whenever there is Uterine dysfunction is common whenever there is disproportion between the presenting part of the fetus disproportion between the presenting part of the fetus and the birth canal.and the birth canal.

Normal labour usually divided into :Normal labour usually divided into :

1 1 –– Latent phase : usually little cervical dilatation but Latent phase : usually little cervical dilatation but considerable changes taken place in the connective considerable changes taken place in the connective tissue components of the cervix.tissue components of the cervix.

2 2 –– Active phase : Friedman subdivided the active phase Active phase : Friedman subdivided the active phase into acceleration phase, phase of maximum slope and into acceleration phase, phase of maximum slope and the deceleration phase.the deceleration phase.

Latent phase :Latent phase : Friedman defined it as the point at which the mother Friedman defined it as the point at which the mother

perceives regular uterine contraction along with perceives regular uterine contraction along with cervical softening and effacement and ends at between cervical softening and effacement and ends at between 3 and 5 cm of dilatation.3 and 5 cm of dilatation.

Prolonged latent phase :Prolonged latent phase :

Defined ( 1963 ) by Friedman and Sachtleben to be Defined ( 1963 ) by Friedman and Sachtleben to be greater than 20 hours in the nullipara and 14 hours in greater than 20 hours in the nullipara and 14 hours in the paras women. These are the 95the paras women. These are the 95thth percentage. percentage.

Factors that affect the duration of the latent phase Factors that affect the duration of the latent phase include :include :

1 1 –– Excessive sedation : conduction analgesia.Excessive sedation : conduction analgesia.

2 2 –– Poor cervical conduction : ( eg. Thick , uneffected Poor cervical conduction : ( eg. Thick , uneffected or undilated )or undilated )

3 3 –– False labour. False labour.

Rest is preferable for correcting prolonged latent Rest is preferable for correcting prolonged latent labour because unrecognized false labour was labour because unrecognized false labour was common, with strong sedation 85 % of females begin common, with strong sedation 85 % of females begin active labour and 10 % cease contraction ( false active labour and 10 % cease contraction ( false labour ) and 5 % develop recurrent abnormal latent labour ) and 5 % develop recurrent abnormal latent labour and require oxytocin stimulation. labour and require oxytocin stimulation.

Active labour :Active labour : It beginsIt begins when the cervix is 3 to 4 cm dilated.when the cervix is 3 to 4 cm dilated.

** active phase abnormalities are the most common active phase abnormalities are the most common abnormalities of labour about 25% of nullipara and 15% abnormalities of labour about 25% of nullipara and 15% of multipara.of multipara.

* * Friedman subdivided active phase problems into Friedman subdivided active phase problems into protraction and arrest disorders. protraction and arrest disorders.

* Protraction defined as a slow rate of cervical * Protraction defined as a slow rate of cervical dilatation or desent. dilatation or desent.

i.e < 1.2 cm dilatation / hour or < 1 cm / hour for i.e < 1.2 cm dilatation / hour or < 1 cm / hour for nullipara or < 1.5 cm / hour or < 2 cm / hour for nullipara or < 1.5 cm / hour or < 2 cm / hour for multipara.multipara.

* Arrest of dilatation defined as 2 hr with no cervical * Arrest of dilatation defined as 2 hr with no cervical change or arrest of descent as 1 hour without fetal change or arrest of descent as 1 hour without fetal descent. descent.

Factors contributing to both protraction and Factors contributing to both protraction and arrest disorders were :arrest disorders were :

1 1 –– Excessive sedation. Excessive sedation.

2 2 –– Conduction analgesia. Conduction analgesia.

3 3 –– Fetal malposition eg. Persistant occipito Fetal malposition eg. Persistant occipito –– posterior. posterior.

In both protraction and arrest disorders, fetopelvic In both protraction and arrest disorders, fetopelvic examination done to diagnose CPD.examination done to diagnose CPD.

Recommended therapy for protraction disorder was Recommended therapy for protraction disorder was expectant management, whereas oxytocin was advised expectant management, whereas oxytocin was advised for arrest disorders in the absence of CPD.for arrest disorders in the absence of CPD.

Second stage of labour :Second stage of labour : The second stage of labour begin when cervical The second stage of labour begin when cervical

dilatation is complete and ends with fetal expulsion. It dilatation is complete and ends with fetal expulsion. It needs duration 50 min for nullipara and 20 min for needs duration 50 min for nullipara and 20 min for multipara. But it is also highly viable.multipara. But it is also highly viable.

the length of the second stage of labour in nullipara the length of the second stage of labour in nullipara was limited to 2 hours and extended to 3 hours when was limited to 2 hours and extended to 3 hours when regional analgesia was used. For multipara 1 hour was regional analgesia was used. For multipara 1 hour was the limit extended to 2 hours with regional analgesia. the limit extended to 2 hours with regional analgesia.

Uterine dysfunction :Uterine dysfunction : This is the most common cause of poor progress in This is the most common cause of poor progress in

labour. Uterine dysfunction in any phase of cervical labour. Uterine dysfunction in any phase of cervical dilatation is characterized by lack of progress, for one dilatation is characterized by lack of progress, for one of the prime characteristic of normal labour is its of the prime characteristic of normal labour is its progression. However, one of the most common error is progression. However, one of the most common error is to treat women for uterine dysfunction who are not yet to treat women for uterine dysfunction who are not yet in active labour. It is more common in primigravida and in active labour. It is more common in primigravida and in older women. There have been 3 significant in older women. There have been 3 significant advances in the treatment of uterine dysfunction :advances in the treatment of uterine dysfunction :

1 1 –– realization that undue prolongation of labour may realization that undue prolongation of labour may contribute to perinatal morbidity and mortality. contribute to perinatal morbidity and mortality.

2 2 –– Use of dilute intravenous infusion of oxytocin in the Use of dilute intravenous infusion of oxytocin in the treatment of certain types of uterine dysfunction.treatment of certain types of uterine dysfunction.

3 3 –– More frequently use of cesarean section delivery More frequently use of cesarean section delivery rather than difficult midforceps delivery when oxytocin rather than difficult midforceps delivery when oxytocin fail or its use is inappropriate. fail or its use is inappropriate.

Assessment of uterine contraction most commonly Assessment of uterine contraction most commonly carried out By clinical examination and by using carried out By clinical examination and by using external uterine tocography, but this only provide external uterine tocography, but this only provide informations about the frequency and duration of informations about the frequency and duration of uterine contraction. Intrauterine pressure catheters are uterine contraction. Intrauterine pressure catheters are available and these give accurate measurement of the available and these give accurate measurement of the pressure generated by the contraction but these rarely pressure generated by the contraction but these rarely necessary. necessary.

A frequency of 4 A frequency of 4 –– 5 contractions per 10 minutes is 5 contractions per 10 minutes is usually considered ideal.usually considered ideal.

Types of uterine contractions :Types of uterine contractions :

Uterine contractions of normal labour are Uterine contractions of normal labour are charecterized by gradient of myometrial activity being charecterized by gradient of myometrial activity being greater and lasting longer at the fundus ( fundal greater and lasting longer at the fundus ( fundal dominant ) and diminished towards the cervix.dominant ) and diminished towards the cervix.

Usually the exciting stimulus starts in one cornue and Usually the exciting stimulus starts in one cornue and then several milliseconds later in the other. The then several milliseconds later in the other. The excitation waves then join and sweeping over the excitation waves then join and sweeping over the fundus and down the uterus.fundus and down the uterus.

* Normal spontaneous contractions often exert * Normal spontaneous contractions often exert pressures of about 60 mm Hg.pressures of about 60 mm Hg.

There are 3 types of uterine dysfunction :There are 3 types of uterine dysfunction :

1 1 –– Hypotonic uterine dysfunction :Hypotonic uterine dysfunction :

No basal hypertonus and uterine contraction is have No basal hypertonus and uterine contraction is have a normal gradient pattern ( synchronus ) but the slight a normal gradient pattern ( synchronus ) but the slight rise in pressure during a contraction is insufficient to rise in pressure during a contraction is insufficient to dilate the cervix.dilate the cervix.

Treatment : Treatment :

1 1 –– Matrenal rehydration. Matrenal rehydration.

2 2 –– ARM. ARM.

3 3 –– IV oxytocin ( syntocinon ) IV oxytocin ( syntocinon )

2 2 –– Hypertonic uterine dysfunction :Hypertonic uterine dysfunction :

Either basal tone is elevated appreciably or pressure Either basal tone is elevated appreciably or pressure gradient is distorted, perhaps by contraction of the gradient is distorted, perhaps by contraction of the mid mid –– segment of the uterus with more force than the segment of the uterus with more force than the fundus. fundus.

3 3 –– Incoordinated uterine dysfunction : Incoordinated uterine dysfunction :

complete asynchronism of the impulses originating in complete asynchronism of the impulses originating in each cornue. each cornue.

Sometimes combination of the last 2 types.Sometimes combination of the last 2 types. Treatment :Treatment :

Sometimes oxytocin effective in coordinating these Sometimes oxytocin effective in coordinating these contractions.contractions.

Dystocia can result from several distinct Dystocia can result from several distinct abnormalities involving the cervix, uterus,abnormalities involving the cervix, uterus,

the fetusthe fetus , ,otherother obstruction in the birth canal or in the obstruction in the birth canal or in the maternal bony pelvis. Quit oftne combination of these maternal bony pelvis. Quit oftne combination of these interaction to produce dysfunction labour. Recently interaction to produce dysfunction labour. Recently term such as cephalopelvic disproportion and failure to term such as cephalopelvic disproportion and failure to progress are often used to describe these dysfunctional progress are often used to describe these dysfunctional labours when cesarean section delivery is necessory.labours when cesarean section delivery is necessory.

* Cephalopelvic disproportion ( CPD ) :* Cephalopelvic disproportion ( CPD ) :

Describe abnormal labour due to disparity between Describe abnormal labour due to disparity between the dimensions of the fetal head and maternal pelvis, the dimensions of the fetal head and maternal pelvis, as to preclude vaginal delivery. It can be due to a large as to preclude vaginal delivery. It can be due to a large head, small pelvis or a combination of the two. head, small pelvis or a combination of the two. Originally describe for overt pelvic contracture due to Originally describe for overt pelvic contracture due to rickets, however now such true CPD is rare and most rickets, however now such true CPD is rare and most disproportions are due to malpositions of the fetal disproportions are due to malpositions of the fetal head- asynchtisim or extension of the bony diameters head- asynchtisim or extension of the bony diameters of the fetal head, or to ineffective uterine contraction. of the fetal head, or to ineffective uterine contraction.

Women of small stature ( < 1.60 m ) with a big baby in Women of small stature ( < 1.60 m ) with a big baby in their first pregnancy are candidate to develop this their first pregnancy are candidate to develop this abnormality. Sometimes the pelvis is unusually small abnormality. Sometimes the pelvis is unusually small due to previous fractures or metabolic bone disease.due to previous fractures or metabolic bone disease.

CPD is suspected if there is :CPD is suspected if there is : 1 – Progress is slow or arrest despite efficient uterine 1 – Progress is slow or arrest despite efficient uterine

contraction. contraction. 2 – The fetal head is not engaged.2 – The fetal head is not engaged. 3 – Vaginal examination shows severe moulding and 3 – Vaginal examination shows severe moulding and

caput formation.caput formation. 4 – The head is poorly applied to the cervix. 4 – The head is poorly applied to the cervix.

Risk factors for poor progress in labour :Risk factors for poor progress in labour :

1 1 –– Small women. Small women.

2 2 –– Big baby. Big baby.

3 3 –– Malpresentation. Malpresentation.

4 4 –– Malposition. Malposition.

5 5 –– Early rupture of membrane. Early rupture of membrane.

6 6 –– Soft tissue / pelvic malformation. Soft tissue / pelvic malformation.

Failure to progress, this term used to indicate lack of Failure to progress, this term used to indicate lack of progressive cervical dilatation or lack of descent. So it progressive cervical dilatation or lack of descent. So it is an observation rather than a diagnosis. is an observation rather than a diagnosis.

Dystocia due to pelvic contraction :Dystocia due to pelvic contraction :

Any contraction of the pelvic diameters that Any contraction of the pelvic diameters that diminishes the capacity of the pelvic can create diminishes the capacity of the pelvic can create dystocia during labour. Pelvic contractions may be dystocia during labour. Pelvic contractions may be classified as follows :classified as follows :

1 1 –– Contraction of the pelvic inlet. Contraction of the pelvic inlet.

2 2 –– Contraction of the mid pelvis. Contraction of the mid pelvis.

3 3 –– Contraction of the pelvic outlet. Contraction of the pelvic outlet.

4 4 –– Generally contracted pelvis ( Combination of the Generally contracted pelvis ( Combination of the above ).above ).