CHPTER 18 DYSTOCIA. 부산백병원 산부인과 R1 이은숙. ABNORMAL LABOR AND FETOPELVIC DISPROPORTION. Etiological classification of dystocia. Dystocia literally, difficult labor abnormally slow progress of labor m/c contemporary indication of primary c/sec Abnormalities of the expulsive forces
and failure to progress are often used to describe these dysfunctional labor when cesarean delivery is necessary
( Freidman 1978, Handa and Laros 1993)
were diagnosed in 80 % of women with active-phase arrest
or to ineffective uterine contracture
of only 0 to 3 cm
some specified period
Concept of 3 functional divisions of labor by Friedman
(collagen & other connective tissue component)
subject to sensitive changes by extraneous factors
(sedation → prolongation, myometrial stimulation → shortening)
① Acceleration phase
usually predictive of the outcome of a particular labor
② Phase of maximum slope
good measure of the overall efficiency of the machine
③ Deceleration phase
more reflective fetopelvic relationship
2nd stage of labor commences after complete cervical dilatation
→ only progressive descent of fetal presenting part is available
to assess the progress of labor
at between 3 and 5 cm of dilatation
-> 85 % begin active labor
-> 10 % cease contractions
-> 5 % recur an abnormal latent phase -> oxytocin stimulation
the mean duration of active phase labor in nulliparas was 4.9 hours
. excessive sedation or conduction analgesia
. fetal malposition (e.g., persistent occiput posterior)
by regional analgesia
a possibly difficult forceps or vacuum extraction but after 3 hours in
the second stage, delivery by cesarean or other operative method
the cervix is 15 mmHg (Caldeyro-Barcia, 1950)
to dilate the cervix.
in each cornu
the need for analgesia, and lower the frequency of instrumental vaginal delivery
area of the pelvic outlet with squatting compared with the
fetal size, or more usually, a combination of both.
or transverse diameter < 12 cm
are contracted -> dystocia is much greater
+ posterior sagittal diameter < 13.5 cm
on the interischial tuberous diameter& posterior sagittal diameter of outlet
of the inlet.
12 hours because of amnionitis
(Chua 1995, Mahood and Dick 1995)
of women achieve 200 to 225 Montevideo units, and 40 percent
achieve at least 300 Montevideo units.
both of these criteria should be met :
more in a 10-minute period has been present for 2 hours without cervical change
at least 4 hours, is necessary before concluding that the
active phase of laber has failed.
or intrathecal-are likely to reduce the reflex urge to push, and at the same time may impair ability to contract the abdominal muscles sufficiently.
are important to avoid comprise of voluntary expulsive efforts.
so that the woman can generate intra-abdominal pressure sufficient
to move the fetal head into position appropriate for outlet forceps
of considerable benefit
ment and the concomitant thickening of upper segment ->
the boundary between the two is marked by a ridge on inner
-> the ring is very prominent
head is not engaged.
fetal intracranial hemorrhage
: amniotomy and oxytocin
-> at 2 hour intervals
-> high-dose oxytocin infusion
-> an intrauterine pressure catherter
-> high-dose oxytocin regimen
of the birth canal