PRACTICETEACHING ON
CEPHALO PELVIC DISPROPORTION
Introduction
A contracted pelvis is one in which either the shape or size is sufficiently
abnormal to cause difficulty in the delivery of a normal-sized fetus.
Disproportion is a term which embraces a wider group and indicates any
disparity in size between the fetus and pelvis that will lead to difficulties in
labor, or dystocia.
CPD
Cephalopelvic Disproportion (CPD) is a condition where the baby has
trouble getting through the birth canal because of the size of the baby's
head, the baby's position, or the size or shape of the mother's pelvis. The
baby's head might be too large, or the mother's pelvis might be too small,
or both
DEFINITION
“Anatomically, contracted pelvis is defined as Anatomically, contracted
pelvis is defined as one where the essential diameters of one or more one
where the essential diameters of one or more planes are shortened by 0.5
cm. ”planes are shortened by 0.5 cm.” ““obstetric definition which states
that obstetric definition which states that alteration in the size and/or shape
of the pelvis of alteration in the size and/or shape of the pelvis of sufficient
degree so as to alter the normal sufficient degree so as to alter the normal
mechanism of labor in an average size baby.” mechanism of labor in an
average size baby.”
Cephalo pelvic disproportion is the disparity in relation between the
head of baby and the mother’s pelvis.
It is a pelvis in which one or more of its diameter is reduced below
the normal by one or more centimeter.
Anatomical - It is a pelvis in which one or more of its diameters
is reduced below the normal by one or more centimeters.
Obstetric - It is a pelvis in which one or more of its diameters is reduced so
that it interferes with the normal mechanism of labor
Causes:-
1. Large baby due to:
• Hereditary factors
• Diabetes
• Post maturity (still pregnant after due date has passed)
• Multiparty (not the first pregnancy)
2. Abnormal fetal positions
3. contracted pelvis
4. Abnormally shaped pelvis
Factors influencing the size and shape of the pelvis:
1. Developmental factor: hereditary or congenital.
2. Racial factor.
3. Nutritional factor: malnutrition results in small pelvis.
4. Sexual factor: as excessive androgen may produce android pelvis.
5. Metabolic factor: as rickets and osteomalacia.
6. Trauma, diseases or tumours of the bony pelvis, legs or spines
Etiology of Cephalopelvic Disproportion Causes in the pelvis
Developmental (congenital):
1. Small gynaecoid pelvis (generally contracted pelvis).
2. Small android pelvis.
3. Small anthropoid pelvis
4. Small platypelloid pelvis (simple flat pelvis)
5- Naegele’spelvis: absence of one sacrala
6- Robert’s pelvis: absence of both sacralae.
7- High assimilation pelvis: The sacrum is composed of 6 vertebrae.
8- Low assimilation pelvis: The sacrum is composed of 4 vertebrae.
9- Split pelvis: splitted symphysis pubis
CAUSES OF CONTRACTED PELVIS
Causes in the pelvis
• Metabolic: - Rickets. - Osteomalacia (triradiate pelvic brim).
• Traumatic: as fractures.
• Neoplastic: asosteoma.
• Infection : TB Causes in the spine
• Lumbar kyphosis
• Lumbar scoliosis
Spondylolisthesis: The5th lumbar vertebra with the above vertebral column
is pushed forward while the promontory is pushed backwards and the tip of
the sacrum is pushed forwards leading to outlet contraction
Causes in the lower limbs
• Dislocation of one or both femurs.
• Atrophy of one or both lower limbs.
N.B. oblique or asymmetric pelvis: one oblique diameter is obviously
shorter than the other. This can be found in:
• Diseases, fracture or tumours affecting one side.
• Pelvis
• History
•Rickets: is expected if there is a history of delayed walking and dentition.
• Trauma or diseases: of the pelvis, spines or lower limbs.
• Bad obstetric history: e.g. prolonged labour ended by: difficult
forceps
caesarean section or still birth
Examination
• General examination:
Gait: abnormal gait suggesting abnormalities in the pelvis, spines or
lower limbs.
Height: women with less than 150 height usually have contracted
pelvis.
Spines and lower limbs: may have a disease or lesion.( kyphosis,…)
Pelvis
General examination:
Manifestations of rickets as:
square head
rosary beads in the costal ridges. pigeon chest
Harrison’s sulcus and bow legs
Dystocia dystrophic syndrome: the woman is
short, obese stocky, sub fertile, has android pelvis and Pelvis Abdominal
examination:
No engagement of the head: in the last 3-4 weeks in prim gravida.
Pendulous abdomen: in prime gravida.
Mal presentations: are more common. Pelvis Pelvimetry:
2 .Imaging pelvimetry: X-ray.
Computed tomography (CT). Magnetic resonance
imaging (MRI) .
N.B.CTand MRI are recent and accurate but expensive and not always
available so the are not in common use. Diagnosis of
Internal pelvimetry is done through vaginal examination
1. The inlet:
a. Palpation of the fore pelvis (pelvic brim): The index and middle fingers
are moved long the pelvic brim. Note whether it is round or angulated,
causing the fingers to dip into a- shaped depression behind the symphysis.
a. Diagonal conjugate: Try to palpate the sacral promontory to measure the
diagonal conjugate
External pelvi metry • Thom’s, Jarcho’sor crossing pelvimeter can be used
for external pelvimetry.
Inter spinous diameter (25cm): between the anterior superior iliac spines.
Inter crestal diameter (28 cm): between the most far points on the outer
borders of the iliac crests.
External conjugate (20cm(. Tuberous diameter
(11cm)
. Radiological pelvimetry Lateral view:
The patient stands with the X-ray tube on one side and the film cassette on
the opposite side.
the anteroposterior diameters of the pelvis, angle of inclination of the
brim, width of sacrosciatic notch, curvature of the sacrum and cephalo-
pelvic relationship.
• Inlet view:
The patient sits on the film cassette and leans backwards so that the plane
of the pelvic brim becomes parallel to the film.
• Outlet view: The patient sits on the film cassette and leans forwards.
Cephalometry
•Ultrasonography: is the safe accurate and easy method and can detect:
The biparietal diameter (BPD) The occiput-
frontal diameter. The circumference of the head.
• Radiology (X-ray: is difficult to interpret
Cephalo pelvic disproportion tests These are done to detect contracted inlet
if the head is not engaged in the last 3-4 week sin a primigravida.
(1) Pinard’s method: • The patient evacuates her bladder and rectum. • The
patient is placed in semi-sitting position to bring the fetal axis
perpendicular to the brim.
(2) Muller - Kerr’smethod: •
It is more valuable in detection of the degree of disproportion.
• Thepatient evacuates her bladder and rectum. • The patient is
placed in the dorsal position.
• The left hand pushes the head into the pelvis and vaginal examination
is done by the right hand while its thumb is placed over the symphysis
to detect disproportion. Cephalo pelvic disproportion tests
Complications Maternal Fetal During pregnancy:
↑retroverted gravid uterus. Malpresentations.
Pendulous abdomen Nonengagement.
Pyelonephritis due to more compression of the ureter. During labour:
Slow cervical dilatation and prolonged labour. PROM and cord prolapse.
Obstructed labour and rupture uterus.
Injury to pelvic joints or nerves from difficult forceps delivery.
Postpartum hemorrhage. Intracranial
hemorrhage. Asphyxia.
Fracture skull. Nerve injuries.
Intra-amniotic infection Contracted pelvis
Complications of Contracted Pelvis During labour:
1.Inertia, slow cervical dilatation and prolonged labour.
2.Premature rupture of membranes and cord prolapse.
3.Obstructed labour and rupture uterus.
4.Necrotic genito-urinary fistula.
5. Injury to pelvic joints or nerves from difficult forceps delivery.
6.Postpartum haemorrhage.
• Foetal:
1. Intracranial haemorrhage.
2. Asphyxia.
3. Fracture skull.
4. Nerve injuries.
Intra-amniotic infection. Complications of Contracted Pelvis
Nursing management
•Check vitals every 4 hourly Monitor both contraction and fetus
continuously
Report immediately the sign of fetal distress
Position the mother in ways to increase the pelvic diameter such as sitting
or squatting which increase the outlet diameter and also aid in fetal descent
• Assess the fetus for hypoxia
Provide support to the client and the family members in coping with stress
of a complicated labor
REFERENCES
American College of Obstetricians and Gynecologists.
ACOG Practice Bulletin No. 33. Diagnosis and management of
cephalopelvic disproportion. Obstetrics Gynecology .
2002;99:159-167.
Houry DE, Salhi BA. Acute complications during pregnancy.
In: Marx JA, ed.Rosen's Emergency Medicine: Concepts and
Clinical Practice. 7th ed. Philadelphia, PA: Elsevier Mosby;
2009:chap 176.
Sibai BM. CPD. In: Gabbe SG, Niebyl JR, Simpson JL, et al.,
eds. Obstetrics: Normal and Problem Pregnancies . 6th ed.
Philadelphia, PA: Elsevier Saunders; 2012:chap 35.
