1) Abnormal uterine action refers to any deviation from normal uterine contractions that can affect the progress of labor. It is one of the leading causes of dystocia or difficult labor.
2) Some types of abnormal uterine action include excessive contractions, abnormal polarity, uterine inertia, spastic lower segment, constriction rings, and generalized tonic contractions.
3) Management depends on the specific type but may include oxytocin stimulation of contractions, artificial rupture of membranes, operative vaginal delivery, or caesarean section if needed to deliver the baby safely. Close monitoring of maternal and fetal wellbeing is important.
2. INTRODUCTION
• Abnormal uterine action is one of the factors causing dystocia
(difficult labor) in which uterine forces are insufficiently strong or
inappropriately coordinated to efface and dilate the cervix (uterine
dysfunction).
• Pelvic contraction is often accompanied by uterine dysfunction
and the two together constitute the most common cause of dystocia.
• Dystocia is the most common current indication for primary
cesarean delivery.
• Similarly, malpresentation or large fetal size (macrosomia) may be
accompanied by uterine dysfunction.
3. REVIEW OF NORMAL UTERINE
ACTION
• Regular interval
• Interval gradually shortens
• Intensity gradually increases
• Discomfort in the back and abdomen
• Associated with cervical dilatation
• Discomfort not relieved by sedation
4. REVIEW OF NORMAL UTERINE
CONTRACTIONS
POLARITY OF UTERUS: When upper segment
contracts, lower segment relaxes.
PACEMAKERS: Two pacemakers situated at each cornua
of uterus generating the contraction in co-ordinated
manner.
PATTERN OF CONTRACTIONS: uterine contraction starts
at cornua, propagates towards lower uterine
segment with decrease in the duration and intensity
of contraction as it moves away from pacemaker.
5. PARAMETERS OF UTERINE
CONTRACTION
• BASAL TONE: 5-20mmHg.
• PEAK PRESSURE: around 60 mm Hg pressure
• FREQUENCY OF CONTRACTION
Adequate uterine contractions are 1 in 3
minutes lasting for 45 seconds with good
relaxation in between.
6.
7. ASSESSMENT OF CONTRACTION
• CLINICAL PALPATION
• TOCODYNAMOMETER with external
transducer- measures duration of contraction
and interval between them but not strength
.
• INTRAUTERINE PRESSURE CATHETER:
Measures the strength of contraction also.
8. Quantitative monitoring
Data measured most commonly
using Montevideo units (MVU).
Montevideo Unit the sum of the
intensity of each contraction in a
10 minute period (in mmHg).
Adequate uterine activity
contraction pattern that generates
> 200 MVUs
9.
10. DEFINITION OF ABNORMAL
UTERINE ACTION
• Any deviation from normal pattern of uterine
contractions affecting the normal course of
labour is designated as abnormal uterine
contraction.
Over all labour abnormalities occur in
• 25%nulliparous
• 10%multiparous
11. EXCESSIVE UTERINE
CONTRACTION
• TACHYSYSTOLE :contractions more than once every 2
minutes.
• HYPERSTIMULATION: the above in response to oxytocin with
FHR abnormality.
• TETANIC UTERINE CONTRACTION: single contraction lasting
for more than 3 minutes .
• HYPERTONIC UTERINE CONTRACTION: Elevated baseline
pressure above 20mm Hg.
12. CLASSIFICATION
• ABNORMAL UTERINE ACTION
– N. POLARITY
• HYPERTONIC DYSFUNCTION
1.PRECIPITATE LABOUR: In the absence of obstruction
2.TONIC CONTRACTION &RETRACTION(Bandls ring):in presence of
obstruction
• HYPOTONIC DYSFUNCTION (UTERINE INERTIA)
– ABNORM. POLARITY
• SPASTIC LOWER SEGMENT
• COLICK Y UTERUS
• CONSTRICTION RING
• GENERALISED TONIC CONTRACTION
• C. DYSTOCIA
13. Precipitate labor
Definition:
It is a labor duration less than 3 hours due to
strong coordinate uterine contractions in absence
of obstruction in the birth canal, and resistance of
the soft tissues. The patient does not feel
cotractions except the last contractions during the
expulsion of the fetus
14. DIAGNOSIS
• It is a retrospective diagnosis as the
patient is usually seen in the 2nd or 3rd
stages of labor. If seen during the first
stage of the labor, the partogram will show
rapid progress of cervical dilatation and
effacement. If seen after
delivery, examination of the mother and
infant should be performed for the
following
15. Complications
• Lacerations of the cervix, vagina and perineum predisposing to:
postpartum hemorrhage and sepsis which is also predisposed to due to
delivery in unsuitable surroundings.
• * Atony: due to uterine exhaustion may lead to postpartum *hemorrhage,
retained placenta and inversion of the uterus.
• *Shock due to heamorrhage and/or pain.
– Fetal:
• * Intracranial hemorrhage: due to rapid compression and
decompression of the fetal head during delivery
• * Fetal injuries
• * Avulsion of the cord
• Neonatal sepsis
16. Management
• Prophylaxis:
• A patient with past history of precipitate labor should be admitted to the
hospital at the first perception of labor pains.
• Rarely if the patient is seen during delivery, general anesthesia (inhalation
by nitrous oxide and oxygen or sedation) may be given to slow down the
course of delivery to prevent forcible bearing down.
• If the patient is seen after delivery: exploration of the birth canal for any
injury and manage accordingly.
• Prophylactic antibiotics if delivery occurred in unsuitable conditions
• Proper examination of the fetus for detection of any complications
17. TONIC UTERINE CONTRACTION
AND RETRACTION
PATHOLOGICAL ANATOMY OF UTERUS:
Contraction increases in intensity ,duration and frequency with
decreased relaxation in between
Retraction continues
Progressive thinning & elongation of lower uterine segment
Development of circular groove b/n upper and lower segment-
called BANDL’S RING.
18.
19. In primigravidae further retraction ceases in response to
obstruction and labour comes to a stand still-a state of
exhaustion.
In multiparae retraction continues with progressive dilatation
and thinning of lower uterine segment
Bandl’s ring moves towards the umblicus
Rupture of lower uterine segment
Fetal jeopardy and death
20. Clinical features
• Patient is anxious looking
• Features of exhaustion and ketoacidosis
• Upper uterine segment is tender and hard
• Lower uterine segment distended and tender
• Groove is seen between the two
21. TREATMENT
• Correction of dehydration & ketoacidosis
• Adequate pain relief
• Parenteral antibiotics
EXCLUDE RUPTURE OF UTERUS
Caesarean delivery in majority of cases
22. UTERINE INERTIA
• . Hypotonic Inertia:
• Definition: Weak, infrequent and ineffective uterine contractions
• Etiology: Not known but the following factors may be associated:
• 1. General factors:
• Primigravida especially elderly.
• Anemia, chronic illness. (Antepartum hemorrhage leads to
anemia that predisposes to inertia.
• Hypertensive states with pregnancy
23. • . Local factors:
• Overdistension of the uterus (e.g.: twins and polyhydramnios).
• Anomalies in development of the uterus (eg: unicornuate,
bicornuate and septate uterus).
• Malpresentations and malposition
•
• Full bladder or rectum.
• Uterine fibroids: Fibroids interfere with proper uterine
contractions.
• Induction of premature labour
24. CLASSIFICATION
• Primary inertia:
• Poor uterine contractions from the start of labor.
• Secondary inertia:
• Uterine contractions become weaker after a period of
good uterine contractions due to uterine exhaustion in cases of
cephalopelvic disproportion (act as a protective mechanism against
rupture uterus).
25. CLINICAL FEATURES
• Labor is prolonged: at various stages of labor (detected clinically by partogram as
e.g.: prolonged latent phase, protraction disorders and arrest of cervical dilatation).
• Uterine contractions are weak, infrequent and have short duration. This can be
detected clinically by:
• Examination: On feeling the contractions abdominally there is weak increase in
the uterine tone, uterine contractions in 10 minutes are less than 3 contractions and
each lasting less than 30 seconds.
• Monitoring using:
• External tocodynamometer: by external sensor over the abdomen.
• The mother & the fetus are usually not seriously affected especially when the
membranes remain intact, apart from prolonged labor.
• If the inertia persists after delivery of the fetus, there is liability for retention of the
placenta (prolonged 3rd stage of labor) and atonic postpartum hemorrhage.
26. COMPLICATIONS
• Mostly that of prolonged labor
• A. Maternal:
• In the 1st stage:
• Nervousness, anxiety, exhaustion and starvation ketoacidosis.
• In the 2nd stage:
• prolonged 2nd stage, increase liability for instrumental delivery and
cesarean section.
• In the 3rd stage:
• retention of the placenta and postpartum hemorrhage
• Subinvolution of the uterus
• Risks of abuse of uterine stimulants.
• B. Fetal:
• Usually no effect apart from fetal infection from prolonged premature
rupture of the membranes
27. MANAGEMENT
• General measures:
• Proper diagnosis that this patient is in active labor (and not in the
prodroma of labor) by proper identification of true labor pains
(rhythmic, increase in strength, frequency and duration and
accompanied by bulge of the bag of forewater and cervical
dilatation.
• Exclusion of cephalopelvic disproportion and malpresentations so as
to be managed accordingly.
• Proper management of the 1st stage of the labor
28. • Oxytocin stimulation:
• Aim:
• To increase the strength, frequency and duration of the uterine
• contractions.
• Precautions before & during use of oxytocin:
• There must be no contraindication to oxytocin. Exclusion of the following is
essential:
• Cephalopelvic disproportion.
• Malpresentations (however oxytocin can be given in cases of breech
provided that the pelvis is adequate and there is no other contraindication).
• Incoordinate uterine action.
• Scar in the uterus.
• Grand multipara.
• Fetal distress.
29. • Close observation of the mother &the fetal heart sounds by continuous fetal
monitoring. If significant deceleration develops, stop the infusion.
• Continuous automatic computer infusion pump: For proper calculation and
adjustment of the dose
Technique of I.V. oxytocin administration:
• Dissolve 2 units (2,000 mIU) in 500 ml of lactated ringer solution so 1
ml contains 4 mIU of oxytocin.
• Assessment of efficiency of uterine contractions:
• a. Clinical:
• The hand is applied on the patient's
abdomen to detect frequency, regularity, duration and strength.
• b. External tocography:
• A tocodynamometer is applied on the
mother's abdomen to record uterine contractions.
30. • Operative interference
• Artificial rupture of the membranes: may be effective
especially in cases of hydramnios (will relieve the overstretch of the
uterine muscles).
• Operative delivery indicated if labor is prolonged beyond 24
hours or if there is fetal distress at any time.
• One of the following may be done:
• Vaginal delivery for example by forceps if the cervix
is fully dilated and the conditions are suitable for vaginal delivery
• Caesarean section: if fetal distress occurs before full
dilatation of the cervix
31. SPASTIC LOWER SEGMENT
• Fundal dominance is lacking
• Reverse polarity
• Lower segment contractions are stronger
• Inadequate relaxation in b/n the contractions
• Premature bearing down
• Cervix loose, oedematus, not well applied to
the presenting part
32. Clinical features
• Patient in agony with unbearable pain
• dehydration and ketoacidosis
• Bladder is distended with often retention of urine
PER ABDOMEN:
• Uterine tenderness
• Increased uterine contraction with poor relaxation in between
• Palpation of fetal parts is difficult
• fetal distress in the form of fetal tachycardia
33. • PER VAGINUM:cervix is thick loose edematous
hanging like a curtain ; not well applied to the
presenting part.
Absence of membranes and meconium
stained liquor may be there.
35. CONSTRICTION RING
Also called Schroeder’s ring.
May appear in all stages of labour.
Localized myometrial contraction forms a ring of circular muscle
fibers of the uterus
Situated at the junction of upper and lower segment
Usually around constricted part of the fetus.
38. FEATURES
• Maternal condition not affected
• Fetal distress may occur
• Ring is not palpable during per abdomen
• Felt in
o first stage during –caesarean section
o Second stage –forceps application
o Third stage –manual removal of placenta
39. Delivery is usually by caesarean section
Ring usually passes of by deepening plane of
anaesthesia.
In case of difficulties ring is cut vertically to
deliver the baby.
40. • Localised incoordinate
uterine contraction
• Undue irritability of
uterus
• Usually at the junction
of upper and lower
uterine segment
• Upper segment
contracts and retracts
with relaxation in
between
• Lower uterine segment
thick and loose
• End result of tonic uterine
contraction and retraction
• Following obstructed labour
• Always at the junction of
upper and lower uterine
segment
• Tonically contracted upper
uterine segment
• Lower uterine segment
thinned out
• CONSTRICTION RING • RETRACTION RING
42. CERVICAL DYSTOCIA
• PRIMARY
I. First birth when ext os
fails to dilate
II. Rigid cervix
III. Insufficient uterine
contraction
IV. Malpresentation and
malposition
• SECONDARY
I. Excessive scarring or
rigidity of cervix from
previous operation or
disease
II. Post delivery
III. Cervical cancer
43. MANAGEMENT:
If only thin rim of cervix left behind- it is pushed
up manually during contraction
If cervix is thinned out but only half dilated –
Duhrssens’s incision is given at 2’oclock and
10 o’clock position followed by forceps or
ventouse extraction
44. GENERALISED TONIC
CONTRACTION
• Pronounced retraction occurs involving whole
of uterus up to internal os.
No physiological differentiation of active
upper segment and the passive lower uterine
segment.Fetus is holded inside the
uterus,usually there is no risk of rupture
uterus
47. FEATURES
PER ABDOMINAL EXAMINATION
• Uterus is smaller in size, tense, tender
• Fetal parts are not palpable
• Fetal heart sounds not audible
PER VAGINAL EXAMINATION
• Dry and oedematus vagina
• Jammed head with a big caput