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Cepahalopelvic disproportion- FAQs Dr.B.S.Bhat Professor and Head Department of Obstetrics and Gynaecology PES-IMSR,Kuppam

Q)Causes of mobile head in a nullipara at term A) 1)Occipitoposterior position 2)CPD 3)Malpresentation 4)Tumours in the lower segment 5)Placenta previa 6)Cord around the neck 7)Tumours of the fetal neck 8)Polyhydrominos 9)Hydrocephalus 10)Distended bladder and rectum

Q)Definition of contracted pelvis -Anatomical definition -Obstetric definition A) -Alteration in the size and/or shape of the pelvis of sufficient degree so as to alter the normal mechanism of labour (Obstetrical definition) - Pelvis in which any essential diameter of the pelvis is shortened by greater than 0.5 cms (Anatomical definition) [Holland and Brews]

Q)Inlet Contraction A) Anteroposterior diameter < 10 cms or Transverse diameter < 12 cms

Q)Midpelvic Contraction Interspinous diameter < 9 cms Interspinous diameter + Posterior Sagittal diameter < 13.5 cms X- Ray pelvimetry essential

Q)Outlet Contraction A) Distance between ischial tuberosities< 8 cms Intertuberous diameter + Posterior sagittal diameter < 15 cms

Q) Definition of CPD A) Disparity in the relation between the head and the pelvis

Q)Types of pelvis A)4 types -Gynaeoid:50% -Antropoid:25% -Android:20% -Platypelloid:05%

-Naegele’s pelvis: Lack of development of one sacral ala -Robert’s pelvis: Lack of development of both sacral alae -Rachitic pelvis: Reniform inlet -Osteomalacic pelvis: Triradiate inlet -Split pelvis: Gap between the pelvic bones -High assimilation pelvis: 6 sacral vertebrae -Low assimilation pelvis: 4 sacral vertebrae

Q)Common causes of contracted pelvis A) -Nutritional and Environmental defects -Diseases or injuries of the pelvis -Developmental defects

Q)Mechanism of labour in Flat pelvis A) -BPD is placed in Sacro-cotyloid diameter and Bi-temporal diameter is in the narrow conjugate (Lateral mobilisation). -Exaggerated parietal presentation- Supersub parietal diameter passes through the brim. -Extreme moulding

Q)Short Stature A) Less than 140 cms

Q) Clinical Pelvimetry A) At the beginning of labour

Clinical pelvimetry Inlet Cavity Outlet Sacral promontory Diagonal conjugate Sacral curvature Pelvic side walls Ischial spines Sacrosciatic notch Subpubic angle Subpubic arch Transverse diameter

Assessment of Pelvic inlet

Assessment of Pelvic inlet

Assessment of Pelvic cavity

Assessment of Pelvic cavity

Assessment of Pelvic outlet

Assessment of Pelvic outlet

Munro Kerr Muller method

Diagnosis of CPD Munro Kerr Muller method No Disproportion Mild Disproportion Major Disproportion

Diagnosis of CPD Chassar Moir’s method: Abdominal method Procedure: Index and middle finger of the right hand are placed over pubic symphysis, with the ulnar border of left hand fetal head is pressed in downwards and backward direction in the axis of pelvic inlet

Diagnosis of CPD Chassar Moir’s method: Inference: Only brim disproportion can be excluded If the head can be pushed in the pelvis without overlapping of bones-No Disproportion If the parietal bones flush with the anterior surface of the symphysis pubis-Minor degree Disproportion If the parietal bone overhangs symphysis pubis-Major degree Disproportion

Diagnosis of CPD Ian Donald method Abdominal method Using 3,4,5th fingers of both hands, head is gripped at sinciput and occiput One of the index fingers usually the left reaches over and identifies position of the top of symphysis pubis The thumbs are pressed backwards against the parietal eminence

Diagnosis of CPD Ian Donald method An assisstant applies his hands to baby’s breech and presses the whole child towards the pelvis At the same time thumbs applied to the parietal eminences press downwards and backwards while the fingers on siniciput and occiput can observe what is happening and the index finger of the left hand is kept as before at the upper margin of pubic symphysis

Diagnosis of CPD Ian Donald method Inference If head can be pushed down into the pelvis without overlapping of parietal bone on pubic symphysis -Disproportion is ruled out If head pushed down a little, slight overlapping of parietal bone evidenced by touch on undersurface of fingers-Minor degree CPD is suspected

Diagnosis of CPD Ian Donald method Inference If head cannot be pushed down and instead parietal bone overhangs the symphysis pubis, displacing the fingers-Major degree CPD is suspected

Diagnosis of CPD Hillis Muller test Bimanual method When contractions is at its peak, an attempt is made to push the presenting part into the pelvis by pressing on the uterine fundus with free hand. The hand in the vagina is used to determine whether or not there is downward mobility of presenting part.

Diagnosis of CPD Hillis Muller test Inference If the presenting part does not move or moves very little, the possibility of CPD is high If the presenting part moves easily into the pelvis, possibility of disproportion is low

Diagnosis of CPD Purandhare’s method: Abdominal method (exaggerated lithotomy position) Procedure: Fetal head grasped by the left hand. 2 fingers of the right hand are placed above pubic symphysis. The fetal head is tried to push down into the pelvis.

Diagnosis of CPD Purandhare’s method: Inference Head enters superior strait-No CPD at brim Head flush with pubic symphysis-Minor degree CPD Head overrides pubic symphysis- Major

Q)Pointers towards CPD in labour A) -Prolonged labour despite augmentation with Oxytocin -Head remaining high at full dilatation -Cervix loosely applied to the head -Excessive caput or irreducible moulding of the fetal head

Q)Trial of Labour A) - It is the conduction of labour in a minor degree CPD ,in an institution under supervision with watchful expectancy, hoping for a vaginal delivery.

Q)Factors responsible for successful trial Force – Efficient uterine contraction Passage – “Give way “ of the pelvis Passenger – Moulding of fetal head

Q)Contraindications for trial of labour Severely contracted pelvis Maternal or fetal complications Medical disorders Previous failed trial of labour Previous stillbirth or spastic child

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