Download CONTRACTED PELVIS. LACERATIONS OF THE BIRTH CANAL

Pregnancy and labor at
fetal malpresentations
and abnormal pelvis
Prepared by O. Stelmakh
The main external pelvic sizes
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D. Spinarun - distance
between anterior superior
iliac spines from both
sides. It has 25-26 cm.
D. Cristarum – distance
between iliac crista from
both sides. It is 28-29 cm.
D.
Trochanterica
–
distance
between
trochanter majors from
both sides. It has 31-32
cm.
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C. Externa - distance
between midpoint of
superior surface of
the symphysis pubis
and suprasacralis
fossa. It has 20-21 cm
Michaelis’ Rhomb
and Solovjov index
Vertical 11cm,
transverse –
10cm
Solovjov index- radiocarpal
joint circumference. 14-16 cm
Additional external pelvic sizes
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Lateral conjugate –is a
distance between the anterior
superior iliac spine and
posterior superior iliac spine of
the same iliac bone. It has
14.5-16 cm.
Oblique conjugate –is a
distance between the right
anterior superior iliac spine to
the left posterior superior iliac
spine. It has .20-21cm.
Additional external pelvic sizes
Anteroposterior diameter of
the pelvic outlet is a distance
between the lower par4t of
symphysis pubis and apex of
the coccyx. It has 9.5 cm.
 Transverse diameter of the
pelvic outlet is a distance
between the posterior portions
of the ishial tuberosities. It has
11.5 cm.
Solovjov’ index. It is estimated
by the circumference of
radiocarpal joint. It has 14-16
cm and indicates into bones’
pelvic thickness.
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Obstetric conjugate (widest
anteroposterior diameter of the pelvic )
– 11cm
Indirect ways of true conjugate
estimation:
Diagonal conjugate, usually
exceeds the obstetric
conjugate by 1.5 to 2 cm.
External conjugate exceeds the
obstetric conjugate by 9 cm.
Vertical dimension of Michael’s’
rhomb
equal
obstetric
conjugate.
Estimation of diagonal conjugate
Fetal head station
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-2 (fixed to pelvic inlet)
-1(small segment of fetal
head in pelvic inlet)
0 (large segment of fetal
head in pelvic inlet)
+1 (fetal head in plane of
greatest dimension)
+2 (fetal head in plane of
least dimension)
+3 (fetal head in the
pelvic outlet)
Diameters of the fetal head at term
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1. The suboccipitobregmatic (9.5 cm, 32cm),
which follows from the middle of the large
fontanel to the undersurface of the occipital
bone.
2. The suboccipitofrontalis (10cm,33 cm) –
from subocipital fossa to border of the hair.
3. The occipitofrontal (12 cm, 34 cm), which
follows a line extending from a point just
above the root of the nose to the most
prominent portion of the occipital bone.
4. The occipitomental (12.5-13 cm, 3941cm), from the chin to the most prominent
portion of the occiput.
5.The sublingquobregmatica (9,5 cm, 32
cm).
6. The biparietal (9.5 cm), the greatest
transverse diameter of the head, which
extends from one parietal boss to the other.
7. The bitemporal (8.0 cm), the greatest
distance between the two temporal sutures.
Transverse lie
Oblique lie
Breech presentations
Circumference of the
buttocks – 32cm
C.of the shoulders – 3941cm
C. of fetal head – 32cm
Circumference of the
buttocks – 34-35cm
C.of the shoulders – 3435cm
C. of fetal head – 32cm
Circumference of the buttocks –
28cm
C.of the shoulders – 34-35cm
C. of fetal head – 32cm
From 30-32 weeks -correcting
gymnastics
External cephalic version – at 3236 weeks of gestation
Management
Breech presentations
– cesarean section !
The manual aid by Tsovyanov I
in frank breech presentation
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Aim: to keep normal fetal
attitude.The extremities are
flexed at the hips and
extended at the knees and
thus the feet lie in close
proximity to the head.
The circumference of the
thorax with the crossing on
it arms and legs is larger
than circumference of the
head and the after-coming
head deliveries easily.
The manual aid by Tsovyanov II
in footling presentations
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The aim: to transform the
footling presentation to the
incomplete breech and to
prepare the maternal ways
to the delivery of the head
and shoulders.
The doctor puts up resistance
to the delivery of the feet.
The feet are flexing and the
footling presentation
becomes complete breech
presentation.
The classic manual aid begins
when the lower angular of the anterior
scapula became visible
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Aim: delivery of the
shoulders and the
head when in 2
pushing efforts they
are not delivered.
There are 4 moments of
the classic manual aid:
I - delivery of the posterior
arm.
II – transformation anterior
arm into posterior one
III – delivery of the second
arm
IV – delivery of the head by
Mauriceau-Levre
maneuver
Dexlefed presentations
Sinciput vertex
D. frontooccipitalis
12cm, 34cm
Brow
D.Mentooccipitalis
13 – 13,5cm, 3941cm
Face
D. hyobregmaticus
9.5cm, 32cm
Sinciput vertex presentation
In vaginal exam: sagittal suture,
large and small fontanels are on
the same level.
The fetal head presents with a
fronto-occipital diameter –
12cm
The leading point is the large
fontanel.
The cardinal movements in labor:
 deflexion;
 internal rotation;
 flexion;
 extension;
 internal rotation of body and
external rotation of fetal head.
Vaginal Delivery is possible in
posterior variety in:
 Not large fetus
 Adequate uterine
contractions
 Normal pelvic sizes
Brow presentation
In vaginal exam: the frontal
suture, the large fontanel,
orbital ridges, eyes, and root
of the nose. The nose and
mouth can not be palpable.
The fetal head presents with a
mento-occipital diameter –
13 – 13,5cm
The leading point is the middle
of the frontal suture.
Vaginal delivery is
impossible, only cesarean
section is recommended.
Face presentation
On vaginal exam: face line
with mouth, nose, the, orbits
and chin are presented
The leading point is chin
The fetal head presents with
hyo-bregmaticus diameter
9,5cm
The cardinal movements in
labor are:
 deflexion;
 internal rotation;
 extension;
 internal rotation of the fetal
body and external rotation
of the fetal head.
Vaginal delivery – in face
posterior(chin anteriorly)
Cesarean section in face
posterior.
CONTRACTED PELVIS
Anatomically contracted pelvis is
characterized by shortening of all or one
diameters of the true pelvis into 1,5 - 2 cm and
more.
Clinically or functional contracted pelvis pelvis with normal dimensions, but vaginally
delivery is impossible due to “cephalopelvic
disproportion”.
The main causes:
 fetal macrosomia
 postdate pregnancy
 uterine inertia
 fetal malpresentation, especially fetal head
extension – sinciput vertex, brow, face anterior
position.
Signs of clinically contracted pelvis
1.Arresting of the head in the pelvic inlet
2.Uterine contractions abnormality.
3. Positive Vasten’ sign
4. Signs of urinary bladder compression.
5. Edema of the cervix, and vaginal walls, productions of fistulas.
6. Danger of uterine rupture – overdistension of lower uterine
segment
7. Pushing occurs in location of fetal head in inlet.
Negative
Positive
At the same level
Uterine rupture
In clinically contracted pelvis – only
cesarean section
Pelvic classification according to form of
contractions
1. Often occurred
 generally contracted pelvis;
 flat pelvis: simple flat pelvis, flat rachitic pelvis, generally contracted flat
pelvis.
2. Rare occurred:
 obliquely contracted pelvis,
 obliqualy dislocated pelvis,
 transverse contracted pelvis,
 osteomalacic pelvis,
 funnel-shaped pelvis,
 spondylolisthetic pelvis,
 contracted pelvis as a result of exostosis and bone tumors.
Management of labor. Cesarean section should be performed in all of these
types of pelvis.
Pelvic classification according
to degree of contraction
Four degrees of pelvic contractions should be
distinguished:
 I degree – True conjugate is 11-9 cm. Vaginal
delivery is possible.
 II degree – True conjugate is 9-7,5 cm. Vaginal
delivery is possible.
 III degree – True conjugate is 7,5 – 5,5 cm
Cesarean section is performed.
 IV – degree – True conjugate is 5.5 cm.
Cesarean section is performed.
Generally contracted pelvis
Is characterized by diminution of all true pelvic diameters
(anteroposterior, transverse, and oblique) into 1-2 cm.
Subpubic arch is narrow.
 Average sizes of the pelvis are:
D. spinarum – 23 cm,
D. cristarum – 26 cm.
D. trochanterica - 29 cm
C. externa – 18 cm
C. diagonalis – 11 cm
C. vera – 9 cm.
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Course of labor in generally
contracted pelvis
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prolongation of labor
considerable fetal head flexion thanks to which it is
elongated in the ocipitofrontal diameter (dolichocephaly)
posterior fontanel is situated into the axis of pelvis
considerable molding of the fetal head. Caput
succedaneum is formed in the area of posterior fontanel
with increasing narrowing of the pubic arch, the occiput
cannot emerge directly beneath the symphysis as a
result perineal tears occur.
Management of labor. Vaginally delivery is possible.
Simple flat pelvis
Is defined as shortening of anteroposterior diameters at
all levels of true pelvis, as a result of this sacrum is
inclined anteriorly to pubis.
 Average sizes of the pelvis are:
D. spinarum – 26cm
D. cristarum – 29 cm
D. trochanterica - 31 cm
C. externa – 18 cm
C. diagonalis – 11 cm
C. vera – 9 cm.
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Flat rachitic pelvis
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True conjugate is shortened.
 Sidewalls tend to converge, as result of this D. spinarum and
D. cristarum are the same.
 Additional promontorium may be presented between 1 and 2
vertebrae of sacrum
 Subpubic arch is shallow and wide
 Top of the sacrum is situated posteriorly that’s why
dimensions of the pelvic outlet are normal or even increased.
Average sizes of the pelvis are:
D. spinarum – 26cm
D. cristarum – 26 cm
D. trochanterica - 31 cm
C. externa – 17 cm
C. diagonalis – 10 cm
C. vera – 8 cm.
Course of labor in
flat pelvis
prolongation of labor;
 sagittal suture arresting in the transverse diameter of the
plane of inlet;
 anterior fontanel is the leading point of the fetal head
 asynclitism should be presented
Management of labor. In the case of posterior asynclitism
cesarean section should be performed. Vaginal delivery
in a flatrachitic pelvis
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Generally contracted flat pelvis
Is characterized by combination of the signs of generally contracted
and flat pelvis.
 Average sizes of the pelvis are:
 D. spinarum – 24cm
 D. cristarum – 25 cm
 D. trochanterica - 28 cm
 C. externa – 16 cm
 C. diagonalis – 9 cm
 C. vera – 7 cm.
Course of labor depends from predominance of kind of pelvis
contraction.
 Management of labor. Cesarean section is the method of choice.