dystocia（II）

8/14/2019 dystocia II

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Dystocia(II)

An hongminDepartment Of Obstetrics & Gynecology


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Definition

Dystocia literally means difficult

labor and it is characterized by

abnormally slow progress of labor

It is the consequence of four distinct

abnormalities that may exist

singly or combination


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Abnormal of the powers(uterinecontractility

and maternal expulsive effort)

Abnormalities of the passage (the birth canal)Abnormalities of passenger (the fetus)

Categories of dystocia


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Hypotonic dysfunction

Hypertonic dysfunction

Uncoordinated dysfunction

Hypotonic dysfunction is uterine

activity characterized by contraction

of the uterus with insufficient force(

24mmHg), irregular or

infrequent rhythm, or both.

Hypotonic dysfunction responds

well to oxytocin.

Hypertonic uterine contractions and uncoordinated

contraction often occur together and are characterized

by elevated resting tone of the uterus and frequent

intense uterine contractions. Oxytocin administration

is generally of no value. Sedation is generally

effective in converting hypertonic contractions to

normal labor patterns.


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Dystocia

Second part: abnormalities of thepassage and the passenger


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Abnormalities of the passage

Bony abnormalities

Soft tissue obstruction of the birth canal

Abnormal placental location


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Pelvic types


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Pelvimetry( )

X-ray pelvimetry


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Pelvic contraction

Birth canal

bony canal

soft canal

abnormal bony canal: pelvic

contraction any contraction of the pelvic diameters

that diminishes the capacity of the pelvis

can creat dystocia during labor


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Pelvic contraction classification

Contraction of the pelvic inlet

contraction of the midpelvis and

pelvic outlet

general contraction of the pelvis

pelvic deformities


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Abnormalities of birth canal

1.Bony pelvic

1)Contracted pelvic inletsimple flat pelvis

rachitic flat pelvis( )


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Anteroposterior d


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2)Contracted midpelvis

(anthropoid pelvis )interischial spinous diameter is smaller than 8cm(spinesare prominent, the pelvic side walls converge or the

sacrosciatic notch is narrow)


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3)Contracted pelvic outlet

(funnel shaped pelvis )diminition of the interischial tuberous diameter to 8cm or less.


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4) Generally contracted pelvis

2cm or more shorter than normal

5) Pelvic deformities

osteomalacic pelvisobliquely contracted pelvis ( )


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Clinical signs of contracted pelvis

2) Contracted pelvic inlet

3) Contracted midpelvis

4) Contracted pelvic outlet


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Diagnosis :

History

Physical examination

Pelvimetry

external pelvimetry

internal pelvimetry

diagonal conjugate 12.5~13cm

bi-ischial diameter 10cm

incisura ischiadica 5~6cm

angle of subpubic arch 90


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Effects on mather and fetus

MOTHER:Inlet

Malpresentation and malposition

prolonged labor

insufficient uterine contraction

midpelvis and outlet

persistant occipitotransverse or occipitoposterior

position

fistula formation

intrapartum infection

threatening rupture or rupture


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Fetus

Prom

Prolapse

Distress

Death

Injury

Infection

2. Abnormal of soft birth canal


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2. Abnormal of soft birth canal

Lower segment of uterus

cervix

vaginal


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Congenital anomalies

Scarring of the birth canalPelvic masses

Low-lying placenta

Abnormal of soft birth canal


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Fetal malposition

Occipitoanterior position 90%

malposition 10%abnormal cephalic posion 6-7%

breech presentation 3-4%

others


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Abnormalities of the passengerA. malposition and malpresentation

a. vertex malposition

persistent occiput posterior

persistent occiput transverse 5%

sincipital presentation 1.08%anterior asynclitism( )

posterior asynclitism 0.5%~0.81%

b. brow presentation 0.03%~0.1%

c. face presentation 0.08%~0.27%d. breech presentation 3%~4%

e. abnormal fetal lie transverse or oblique lie0.25%


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Persistant occipitoposterior

(transverse) position

Causes

abnormal pelvis:transverse narrowing

of the midpelvis

flexion not well

hypotonic uterine dysfunction


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Face presentation


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Breech presentation

Incidence

breech presentation is common

remote from term.

3-4% of singleton deliveries

Position

LSA, LST LSP. RSA, RST, RAP


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Causes

Uterine relaxation

limited uterine cavity

fetal head obstructed


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Breech presentation

complete(mixed) breech presentation

frank breech presentation

incomplete breech presentation

knee or footling presentation

the lower extremities are flexed at the hips

and extended at the knees, and thus thefeet lie in close proximity to the head.

It appears most commonly

differs in that one or both knees are

flexedone or both hips are not flexed and

one or both feet or knees lie below

the breech, that is, a foot or knee islowermost in the birth canal


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Effects

Maternal greater frequency of operative delivery

higher maternal morbidity and slightly higher mortalit PROM

secondary hypotonic uterine dysfunction

puerperium infection postpartum haemorrhage

laceration of cervix


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Effects

Fetus

PROM

cord prolapse

fetal distress even death

newborn asphyxia

brachial plexus injury


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Extraction of breech


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B. Fetal macrosomia

large for gestational

age(LGA) 400 0gshou lder dystosia


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. Fetal malformation


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Operative delivery

1)forceps

operations

2)Vacuumextractor


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2)Vacuum

extractor

3)Cesarean section


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3)Cesarean section


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Main point of dystocia


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Main point of dystocia

managemnet


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:

1.The definition and classification

of dystosia

2.How to deal with uterine inertia

during the first stage of labor ?


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THANKS FOR YOUR ATTENTION

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dystocia（II）