Contracted Pelvis
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Transcript of Contracted Pelvis
KABERA René, MD
Family Physician
KABUTARE HOSPITAL
RWANDA
CONTRACTED PELVIS
PLAN
• Introduction
• Definition
• Types of Pelvis
• Risk factors
• Diagnosis
• Management
• References
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INTRODUCTION
Knowledge of the shape and dimensions of the
normal female pelvis is essential for a proper
understanding of the second stage of labor and its
abnormalities since the body pelvis is an important
component which determines the birth canal
structure.
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DEFINITION
• Anatomical definition: It is a pelvis in which
one or more of its diameters is reduced below
the normal by one or more centimeters.
• Obstetric definition: It is a pelvis in which one
or more of its diameters is reduced so that it
interferes with the normal mechanism of labor.
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TYPES :CALDWELL-MOLOY CLASSIFICATION
Anthrapoid (25-30%)
Android (17%)
Gynecoid (50%)
Platypelloid 3% APRIL 2013
CLASSIFICATION OF MERGER (FRENCH)
Robert Merger 1903-1986
• Bassin aplati
• Bassin transversalement retreci
• Bassin generalement retreci et aplati
• Bassin generalement retreci
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CLASSIFICATION OF THOMS
American obstetrician Herbert Thoms 1885-1972
• Dolichopellic Pelvis :True conjugate > Transverse
• Mesatipellic Pelvis :True conjugate = Transverse or < of 1 cm
• Brachypellic Pelvis :True conjugate < Transverse of 1 to 3 cm
• Platypellic Pelvis :True conjugate < Transverse of 3 cm and
above
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2 INNOMINATE
BONES :
ILIUM
ISCHIUM
PUBIS
SACRUM
COCCYX
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RISK FACTORS
Factors influencing the size and shape of the pelvis
• Developmental factor: hereditary or congenital.
• Racial factor.
• Nutritional factor: malnutrition results in small pelvis.
• Sexual factor: as excessive androgen may produce
android pelvis.
• Metabolic factor: as rickets and osteomalacia.
• Trauma, diseases or tumors of the bony pelvis, legs or
spines.
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DIAGNOSIS
History
• Trauma or diseases: of the pelvis, spines or
lower limbs.
• Bad obstetric history: e.g. prolonged labor ended
by difficulty; forceps, caesarean section or still
birth.
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DIAGNOSIS
Examination
General examination
• Abnormal gait.
• Stature: women < 150 cm.
Abdominal examination
• Pendulous abdomen in primigravida.
• Non engagement in last 3-4 wks of pregnancy in
primigravida.
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ABDOMINAL PALPATION
NOT ENGAGED (PONDULOUS)
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DIAGNOSIS
Pelvimetry
� External pelvimetry is of little value as it measures
diameters of the false pelvis.
Measures :Michaelis,Trillat
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DIAGNOSIS
�Internal pelvimetry (done by per vagina exam)
• The inlet:-Pelvic brim, Pelvic cavity
• Palpation of the forepelvis (pelvic brim): V-shaped depression.
• Diagonal conjugate: <11.5 cm (not used if the head is engaged).
• Ischeal spine :pelvic cavity
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Diagnosis :Internal pelvimetry-Inlet DIAGONAL CONJUGATE AND SUBPUBIC ANGLE
ASSESSMENT
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DIAGNOSIS: INTERNAL PELVIMETRY-OUTLET
• Bituberous diameter : ≤8 cm
• Mobility of the coccyx: fixed
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WIDE SUBPUBIC ANGLE IN GYNECOID TYPE
NARROW IN ANDROID TYPE
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MANAGEMENT
The true
conjugate
Bituberous
diameter
Decision
> 9 > 8 cm Vaginal delivery
8-9 cm > 8 cm Trial of labor
8-9 cm ≤ 8 cm C-section
< 8 cm > or < 8cm C-section
N.B: The fetal measurements must be considered !!! APRIL 2013
MANAGEMENT
Degrees of Contracted inlet pelvis
• Minor degree: The true conjugate is 9-10 cm. It
corresponds to minor disproportion. Vaginal delivery.
• Moderate degree: The true conjugate is 8-9 cm. It
corresponds to moderate disproportion. Trial of labor.
• Severe degree: The true conjugate is 6-8 cm. It
corresponds to marked disproportion. C-section.
• Extreme degree: The true conjugate is less than 6 cm,
vaginal delivery is impossible even after craniotomy as the
bimastoid diameter (7.5 cm) is not crushed. C-section.
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REFERENCES
• Geneva Foundation for Medical Education and
Research, Contracted Pelvis, Obstetrics simplified -
diaa M.Ei-mowafi.2009
• Williams Obstetrics .Section IV. Labor and Delivery.
Chapter 20. Dystocia: Abnormal Labor, 22nd ed. 2005.
• Current Obstetrics and Gynecologic diagnosis and
treatment. Section III Pregnancy at risk. Abnormalities
of the passage, 9th ed. 2003.
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Thank you
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