Abnormal Labour

Question 1

What is prolonged labour?

Answer 1

Labor is prolonged when combined duration of 1st and 2nd stage is more than the arbitrary time limit of 18hrs
 Its prolonged if
a) Cervical dilatation rate is < 1 cm/hr and
b) Descent of presenting part is < 1 cm/hr for a period of minimum 4 hours observation (WHO)

Question 2

What causes prolonged labour in stage 1?

Answer 2

First stage: Failure to dilate the cervix is due to
1. Power: Abnormal uterine contraction e.g., uterine inertia (common) or very strong inco-ordinate uterine
contraction
2. Passage: :
a) Unfavourable pelvic types (Android or anthropoid), contracted pelvis (healing after a pelvic fracture
distorts the orthopaedic lines)
b) Cervical dystocia,
c) Pelvic tumor, or even full bladder
d) Uterine structural abnormalities
e) Submucosal uterine fibroids in lower segment of the uterus
f) Placenta praevia
g) Cervical stenosis
h) Carcinoma of the cervix
i) Extensive genital warts
 Passenger: Macrosomia, malpresentation (face, brow), malposition (OP), cord entanglement &
congenital anomalies- (hydrocephalus)
 Others: Injudicious (early) administration of sedatives and analgesics before the active labor begins.

Question 3

What causes prolonged latent phase?

Answer 3

 Prolonged latent phase is that which exceeds 20 hrs in primigravidae or 14 hrs in multiparae
 Causes of prolonged latent phase include;
a) Unripe cervix
b) Malposition and malpresentation
c) Cephalopelvic disproportion and
d) Premature rupture of the membranes

Question 4

Management of prolonged latent phase

Answer 4

Management of prolonged latent phase
 Expectant management unless there is any indication (for the fetus or mother) for expediting the delivery
 Rest and analgesic are usually given
 If augmentation is needed, preferably use medical methods (oxytocin or prostaglandins) and avoid amniotomy

Question 5

What causes prolonged labour in stage 2?

Answer 5

Second stage: Sluggish or non-descent of presenting part in 2nd stage is due to:
1. 2. Power: a) Uterine inertia, b) Inability to bear down, c) Epidural analgesia, d) Constriction ring.
passage: a) CPD, android pelvis, contracted pelvis, b) Undue resistance of pelvic floor or perineum due to
spasm or old scarring, c) Soft tissue pelvic tumour
3. Passenger: a) Malposition (occipito-posterior), b) Malpresentation, c) Big baby (4) Congenital
malformation of the baby.

Question 6

How to diagnose prolonged labour

Answer 6

Diagnosis
 Prolonged labor is not a diagnosis but it is the manifestation of an abnormality,
 Establish the cause by thorough abdominal and vaginal examination.
 Intranatal imaging (radiography, CT or MRI) determine fetal station, position and pelvic shape and size

Question 7

Fetal risks for prolonged labour

Answer 7

Fetal risks of prolonged labour
a) Hypoxia due to diminished uteroplacental circulation especially after rupture of the membranes.
b) Intrauterine infection
c) Intracranial stress or hemorrhage
d) Increased operative delivery

Question 8

Maternal risks of prolonged labour

Answer 8

Maternal risks of prolonged labour
a) Distress
b) Postpartum hemorrhage
c) Trauma to the genital tract—concealed or revealed such as cervical tear, rupture uterus
d) Increased operative delivery (vaginal instrumental or difficult cesarean)
e) Puerperal sepsis
f) Subinvolution

Question 9

What is Obstructed labour

Answer 9

Obstructed labour
 Failure of the presenting part to descend into the pelvis despite adequate uterine contractions
 Obstructed labor is one where in spite of good uterine contractions, the progressive descent of the presenting part is
arrested due to mechanical obstruction

Question 10

Causes of obstructed labour

Answer 10

a) Passage:
1. Bony- Cephalopelvic disproportion and contracted pelvis are common causes. –Basically a mismatch between
the fetal head and the pelvis
 CPD implies anatomical disproportion between the fetal head and maternal pelvis. It can be due to a large
head, small pelvis or a combination of the two.
2. Soft tissue obstructions: cervical dystocia
3. Pelvic shape
 Gynecoid ( most women and most favourable for childbirth )
 Android ( typical male type but some women have it )
 Anthropoid ( associated with persistent opp)
 Platypelloid
4. Small pelvis ( malnutrition in Childhood)
5. Pelvic tumours-eg fibroids
b) Passenger:
1. Malposition or malpresentation, abnormal lie (transverse lie), Brow presentation occipito-posterior position
(associated with deflexion of the fetal head and presents a larger skull diameter to the maternal pelvis),
Compound presentation
2. Congenital malformations of fetus—hydrocephalus (commonest), fetal ascites, double monsters
3. Big baby,
4. Locked twins
5. Fetal thyroid and neck tumours may cause extension at the fetal neck.

Question 11

Contracted pelvis

Answer 11

 Defined as one where the essential diameters of one or more planes are shortened by 0.5 cm
 Obstetric definition states that alteration in the size and/or shape of the pelvis of sufficient degree so as to alter the
normal mechanism of labour in an average size baby

Question 12

Common causes of contracted pelvis

Answer 12

Common causes of contracted pelvis are:
1. Nutritional and environmental defects
2. Diseases or injuries affecting bones of pelvis
• Fracture, tumours, tubercular arthritis;
• Spine- Kyphosis, scoliosis, spondylolisthesis, coccygeal deformity;
• Lower limbs- Poliomyelitis, hip joint disease.
• Rachitic flat pelvis: Rickets in early childhood cause bones to remain soft and unossified. Changes occur in
the bony pelvis due to weight bearing. The classic changes are in the pelvic bone
• Osteomalacic pelvis: affects mature ladies. Deformity is caused by softening of pubic bones due to calcium
and vitamin D deficiency and lack of exposure to sunrays.
3. Development defects- Naegele’s pelvis (produced due to arrested development of one ala of the
sacrum), Robert’s pelvis; High or low assimilation pelvis.

Question 13

Pathophysiology of contracted pelvis

Answer 13

Pathophysiology
 Pathological anatomy of the uterus: There is gradual increase in intensity, duration and frequency of uterine
contraction.
 Relaxation phase becomes progressively less and less; ultimately a state of tonic contraction develops.
 Retraction, however, continues. The lower segment, elongates and becomes progressively thinner to accommodate
the fetus driven from the upper segment.
 A circular groove encircling the uterus is formed between the active upper segment and
the distended lower segment, called pathological retraction ring (Bandl’s ring).
 Due to pronounced retraction, there is fetal jeopardy or even death

Question 14

Bladder implications from contracted pelvis

Answer 14

 Bladder: is pushed into abdomen and due to compression of urethra between the
presenting part and symphysis pubis, the pt fails to empty the bladder.
 Transverse depression at the junction of superior border of bladder and distended
lower segment develops.
 Bladder wall is traumatized, leading to blood stained urine, a common finding in obstructed labor.
 Base of bladder and urethra, are nipped in between the presenting part and symphysis pubis and may undergo
pressure necrosis, later on becomes infected and may slough off resulting in genitourinary fistula

Question 15

CF of contracted pelvis

Answer 15

Patient is in agony from continuous pain and discomfort and becomes rest-less
 Features of exhaustion and ketoacidosis are evident
 Abdominal palpation reveals- (a) Upper segment is hard and tender (b) Lower segment is distended and tender.

Question 16

Complications of obstructed labour

Answer 16

Maternal
1. Exhaustion, dehydration and metabolic acidosis
2. Infections ( prolonged ROM )- Genital sepsis
3. Trauma to uterus- vagina , bladder, rectum - Genitourinary fistula or rectovaginal fistula
4. Postpartum hemorrhage and shock
5. Secondary amenorrhoea following hysterectomy due to rupture or due to Sheehan’s syndrome.
6. Death- are due to rupture of the uterus, shock and sepsis with metabolic changes
Fetal
1. Asphyxia,
2. Acidosis due to fetal hypoxia and maternal acidosis.
3. Brain damage ,
4. Intracranial hemorrhage is due to supermoulding
5. Infection. All these lead to increased perinatal loss.
6. Fetal death

Question 17

Cephalopelvic disproportion

Answer 17

 CPD) implies anatomical disproportion between the fetal head and maternal pelvis.
 State where the normal proportion between the size of fetus to the size of the pelvis is disturbed.
 Disparity in the relation between the large head, small pelvis and or a combination of the two

Question 18

Criterion for pelvic inlet and outlet contraction

Answer 18

Pelvic inlet is contracted if
 Obstetric conjugate is < 10 cm or
 The greatest transverse diameter is < 12 cm or
 Diagonal conjugate is < 11 cm.
Outlet is contracted if inter ischial tuberous diameter is 8 cm or less. Often associated with midpelvic contraction.

Question 19

Cephalopelvic disproportion is suspected in labour if:

Answer 19

Cephalopelvic disproportion is suspected in labour if:
 Progress is slow or actually arrested despite of efficient uterine contractions;
 The fetal head is not engaged;
 Vaginal examination shows severe moulding and caput formation;
 The head is poorly applied to the cervix.

Question 20

Diagnosis of cephalopelvic disproportion

Answer 20

Diagnosis of cephalopelvic disproportion (cpd) at the brim
Presence and degree of CPD at the brim is ascertained by:
1. Clinical- In multigravida, a previous H/O SVD of an average size baby, excludes contracted pelvis reasonably.
 But rule out disproportion in a primigravida with non engagement of the head even during labor.
a) Abdominal method;
• Place pt in dorsal position with thighs slightly flexed and separated.
• Grasp the head with the left hand.
• Place index and middle of the right hand above the symphysis pubis
• Keep inner surface of fingers in line with anterior surface of symphysis
pubis
• Note degree of overlapping, if any, when the head is pushed
downwards and backward
• Findings:
i) No disproportion- If head is pushed down in pelvis without overlapping of parietal bone on the
symphysis pubis
ii) Moderate disproportion- if head is pushed down a little but there is slight overlapping of the parietal
bone evidenced by touch on the under surface of the fingers (overlapping by 0.5 cm or 1/4” which is the
thickness of the symphysis pubis)
iii) Severe disproportion- Head cannot be pushed down and instead the parietal bone overhangs the
symphysis pubis displacing the fingers
b) Abdominovaginal (Muller-Munro Kerr)-.
• Bimanual method by placing vaginal finger tips at the level of ischial spines to note the descent of the
head. 2 fingers of the right hand are introduced into the vagina with the finger tips placed at the level of
ischial spines and thumb is placed over the symphysis pubis. The head is grasped by the left hand and
is pushed in a downward and backward direction into the pelvis
i) No disproportion; head can be pushed down up to the level of ischial spines and there is no
overlapping of the parietal bone over the symphysis pubis
ii) Slight or moderate disproportion; head can be pushed down a little but not up to the level of ischial
spines and there is slight overlapping of the parietal bone
iii) Severe disproportion- head cannot be pushed down and instead the
parietal bone overhangs the symphysis pubis displacing the thumb
2. 3. Imaging pelvimetry- Radio-pelvimetry, CT and MRI.
Cephalometry- (a) Ultrasound; (b) Magnetic Resonance Imaging; (c) X-ray

Question 21

Aims of CPD treatment

Answer 21

The underlying principles are:
1. To relieve the obstruction at the earliest by a safe delivery procedure
2. To combat dehydration and ketoacidosis
3. To prevent / control seps

Question 22

Management of CPD

Answer 22

Preliminaries:
 Fluid electrolyte balance and correction of dehydration and ketoacidosis are done by rapid infusion of Ringer’s
solution; one liter is given as a rapid infusion. At least 3 liters of fluid are required to correct clinical dehydration.
 A vaginal swab is taken and sent for culture and sensitivity test.
 Bld sample is sent for group & cross matching & a unit of bld should be at hand prior to any operative intervention.
 Broad spectrum Antibiotics IV to prevent infections
Obstetric management
 Before proceeding for definitive operative treatment, rupture of the uterus must be excluded.
 A balanced decision should be taken about the best method of relieving the obstruction with least hazards to the
mother and fetus.
 Frantic attempt to deliver a moribund baby by a method ignoring the risk involved to the mother is bad obstetrics.
 There is no place of “wait and watch”, neither any scope of using oxytocin to stimulate uterine contraction.
 It is usually safer to deliver the baby through Caesarean section.
 In the past, attempts to deliver vaginally using destructive operation e.g., Symphysiotomy, were done but those are
not advisable in modern practice as they cause more maternal morbidity including a ruptured uterus.
 A Caesarean Section is therefore recommended for delivery.

Question 23

Prevention of CPD

Answer 23

Antenatal detection of factors likely to cause prolonged labor (big baby, small women, malpresentation & position)
 Intranatal: Continuous vigilance, use of partograph and timely intervention of a prolonged labor due to
mechanical factors can prevent obstructed labor.
 Failure in progress of labor in spite of good uterine contractions for a reasonable period (2–4 hours) is an impending
sign of obstructed labor

Question 24

Shoulder dystocia

Answer 24

Shoulder dystocia (Sh. D)
 Is the inability to deliver the fetal shoulders after delivery of the head, without the aid of specific maneuvers
(i.e. other than gentle downward traction on the head).
 Shoulder dystocia occurs when either the anterior or the posterior (rare) fetal
shoulder impacts on the maternal symphysis or on the sacral promontory.
 It has been defined as delivery of the shoulder requiring the use of additional
obstetric manoevres to release the shoulders after gentle downward traction to fetal
head has failed’.
 Objective definition : a prolongation of the head-to-body delivery interval of more
than 60 seconds

Question 25

Pathophysiology of shoulder dystocia

Answer 25

 As operative vaginal delivery of malposition and malpreresntation has declined, Sh.D has emerged as one of the more important clinical and medico-legal complications of vaginal delivery  Depends on the size of the maternal pelvis in relation to the size of the fetus and occurs from impaction of the shoulder on the pubic symphysis anteriorly or the sacral promontory posteriorly.  Shoulder dystocia results from a size discrepancy between the fetal shoulders and the pelvic inlet when: 1. Bisacromial diameter is large relative to the biparietal diameter 2. Pelvic prim is flat rather than gynecoid  During vaginal delivery, fetal head and shoulders rotate to make use of the widest pelvic diameters.  After delivery of the head, restitution occurs and the shoulders rotate into the anteroposterior (AP) diameter.  This makes use of the widest AP diameter of the pelvic outlet.  However, if the shoulders have not entered the pelvic inlet, the anterior shoulder may become caught above the symphysis pubis.  Occasionally, both shoulders (or rarely, posterior shoulder) may remain above the pelvic brim

Question 26

Types of shoulder dystocia

Answer 26

Based on the level of impaction a) High Shoulder Dystocia Both shoulders fail to engage (Bilateral Sh.D). (Rare)  More common with mid - pelvic assisted delivery  This presentation often requires a cephalic replacement. (Most difficult) b) Low Shoulder Dystocia  Failure of engagement of the anterior shoulder (Unilateral Sh.D).  The commonest: Usually easily dealt with by Standard techniques Based on the position a) b) c) Anterior shoulder dystocia- anterior shoulder get impacted/ caught up above the maternal symphysis pubis. Posterior shoulder dystocia- shoulder is caught up under the sacal promontory. Bilateral shoulder dystocia- both shoulders fail to engage

Question 27

RF for shoulder dystocia

Answer 27

1. Fetal macrosomia but in about 50% of cases of shoulder dystocia occur with normal size baby of < 4 Kg!! 2. Obesity / Excessive maternal weight gain 3. Maternal diabetes / Prior gestational diabetes 4. Midpelvic instrumental delivery (more following ventouse than forceps) 5. Postmaturity/Post term 6. Multiparity 7. Advanced maternal age 8. Anencephaly 9. Fetal ascites.

Question 28

Complications of shoulder dystocia

Answer 28

Maternal Complications (25%) 1. Postpartum hemorrhage 2. Vaginal laceration 3. Perineal tears- 2nd & 3rd degree tears 4. Cervical laceration 5. Increased operative delivery and morbidity Fetal Complications of Sh D  Injuries are a common outcome associated with shoulder dystocia and may occur despite use of proper standard obstetric manoeuver 1. Asphyxia 2. Brachial plexus injuries- (plexopathy) due to stretch, Erb palsy, Klumpke palsy. Traction combined with fundal pressure is associated with a high rate of brachial plexus injuries and fractures  < 10% of deliveries complicated by shoulder dystocia will result in brachial plexus injury. 3. Fractures of the humerus are the most commonly reported injuries associated with 4. Clavicular Fractures shoulder dystocia 5. Sternomastoid hematoma during delivery. 6. Perinatal morbidity and mortality

Question 29

Diagnosis of shoulder dystocia

Answer 29

Diagnosis of shoulder dystocia:  Definite recoil of the head back against the perineum (turtle-neck sign)  Inadequate spontaneous restitution  Fetal face becomes plethoric.

Question 30

What are the principles of shoulder dystocia management?

Answer 30

Principles of shoulder dystocia a) Call for extra help b) To clear infant’s mouth and nose c) Avoid giving traction over baby’s head d) Never to apply fundal pressure as it causes further impaction of the shoulder e) To perform wide mediolateral episiotomy as it provides space posteriorly f) To involve anesthetist (as analgesia is ideal) & pediatrician (for infant’s resuscitation).

Question 31

Management of shoulder dystocia

Answer 31

1) HELP- Call for help: assistants, anesthesiologist-  Document time the head is delivered, which shoulder it is anterior and the times at which each manoeuvre is employed. 2) Initial gentle attempt of downward traction on the head- grasp Head and neck and take them posteriorly while suprapubic pressure is applied by an assistant slightly towards the side of fetal chest. This will reduce the bisacromial diameter and rotate the anterior shoulder towards the oblique diameter. 3) Episiotomy - Generous episiotomy. 4) Suprapubic pressure 5) McRobert manoeuver, (Exaggerated hyperflexion of the thighs upon the abdomen.) & Suprapubic pressure in the direction of the Fetal face  Abduct maternal thighs and sharply flex them onto her abdomen  Symphysis pubis is rotated upwards and decrease in angle of pelvic inclination.  That does not increase pelvic dimensions but straightens sacrum relative to lumbar vertebrae.  Employ this maneuver first If McRoberts manoeuver failed: 6) Woods corkscrew - internal manoeuvres  The hand is placed behind the posterior shoulder of the fetus.  Shoulder is rotated progressively 1800 in a corkscrew manner so that impacted anterior shoulder is released.  Simultaneous suprapubic pressure is applied.  This pushes bisacromial diameter from antero-posterior diameter to an oblique diameter. 7) Delivery of P. shoulder  By inserting a hand into the posterior vagina and ventrally rotating the arm at the shoulder  Introduce hand into the vagina along the fetal posterior humerus.  Arm is then swept across the chest & thereafter delivered by gentle traction over the perineum. May cause fracture of clavicle or humerus or both. 8) Zavanelli - pushing fetus back to the uterus and delivering by cesarean section) or symphysiotomy are done rarely  Fetal head is manually returned to its prerestitution position, and then slowly replaced into the vagina and then into the uterus by steady upward pressure against the head.  Delivery is then accomplished by cesarean delivery.  A uterine relaxant may be required to carry out this procedure  Used if patient has received epidural analgesia or heavy analgesia with obstetric facilities for emergency CS 9) “Gaskin” or All fours maneuver  It consists of placing the patient onto her hands and knees  Increases the anterior–posterior diameter of the inlet. In this position, posterior arm can be delivered.  It allows rotational movement of the sacroiliac joints resulting in l-cm to 2- cm increase in the sagittal diameter of the pelvic outlet.  It disimpact shoulders, & allowing it to slide over the sacral promontory  Effective also for bilateral Sh.D.  Used at all circumstances except if the patient has received epidural analgesia, heavy analgesia or anesthesia 10) Cleidotomy: Intentional fracture of one or both clavicles may be cut with scissors to reduce the shoulder girth. This is applicable to a living anencephalic baby as a first choice or in a dead fetus 11) Symphysiotomy - maternal symphysis is divided, NB: When shoulder dystocia is anticipated, prophylactic McRobert position is recommended  Shoulder dystocia drill should be as important as CPR for the mother and neonate.  This should be taught and practiced regularly, by all staff involved with delivery