Abnormal uterine action
INTRODUCTION:
- Any deviation of the normal pattern of uterine contractions affecting the course of labor is designated as disordered or abnormal uterine action.
TYPES:
PRECIPITATE LABOUR:
- A labour lasting less than 3 hours
Aetiology:
It is more common in multiparas when there are:
- Strong uterine contractions
- Small sized baby
- Roomy pelvis
- Minimal soft tissue resistance.
Complications:
Maternal:
- Lacerations of the cervix, vagina and perineum.
- Shock.
- Inversion of the uterus.
Postpartum haemorrhage:
- No time for retraction
- Lacerations.
- Sepsis due to :Lacerations,Inappropriate surroundings.
Foetal:
- Intracranial haemorrhage due to sudden compression and decompression of the head.
- Foetal asphyxia due to: Strong frequent uterine contractions reducing placental perfusion, lack of immediate resuscitation.
- Avulsion of the umbilical cord.
- Foetal injury due to falling down.
Management:
Before delivery:
- Patient with previous precipitate labour should be hospitalized before expected date of delivery .
During delivery:
- Inhalation anaesthesia: Nitrous oxide and oxygen .
- Tocolytic agents: ritodrine
- Episiotomy:Avoid perineal lacerations and intracranial haemorrhage.
EXCESSIVE UTERINE CONTRACTION AND RETRACTION:
Physiological Retraction Ring
- It is a line of demarcation between the upper and lower uterine segment present during normal labour and cannot usually be felt abdominally.
Pathological Retraction Ring (Bandl’s ring)
- It is the rising up retraction ring during obstructed labour due to marked retraction and thickening of the upper uterine segment while the relatively passive lower segment is markedly stretched and thinned to accommodate the foetus.
- The Bandl’s ring is seen and felt abdominally as a transverse groove that may rise to or above the umbilicus.
- Clinical picture: is that of obstructed labour with impending rupture uterus
HYPOTONIC UTERINE INERTIA:
- The uterine contractions are infrequent, weak and of short duration.
Aetiology:
General factors:
- Primigravida
- Anaemia and asthenia
- Anxiety and fear
- Hormonal
- Improper use of analgesics
Local factors
- Overdistension of uterus
- Uterine hypoplasia
- Myomas of uterus
- Malpresentations, malpositions and cephalopelvic disproportion.
- Full bladder and rectum
Types:
- Primary inertia: weak uterine contractions from the start.
- Secondary inertia: inertia developed after a period of good uterine contractions when it failed to overcome an obstruction so the uterus is exhausted
Clinical Features:
- Prolonged Labour
- Infrequent Uterine contractions ( weak and of short duration).
- Slow cervical dilatation.
- Membranes intact.
- Maternal anxiety due to prolonged labour.
- More susceptibility for retained placenta and postpartum haemorrhage due to persistent inertia.
- Tocography: shows infrequent waves of contractionswith low amplitude.
Management
- Examination to detect disproportion,malpresentation or malposition and manage according to the case.
- First stage
- Prophylactic antibiotics in prolonged labourparticularly if the membranes are ruptured.
- Amniotomy
- Oxytocin
Operative delivery:
- Vaginal delivery: by forceps, vacuum or breech extraction
Caesarean section is indicated in:
- Failure of the previous methods
- Contraindications to oxytocin
- Foetal distress before full cervical dilatation.
HYPERTONIC UTERINE INERTIA (Uncoordinated Uterine Action):
Types:
- Colicky uterus: incoordination of the different parts of the uterus in contractions.
- Hyperactive lower uterine segment: so the dominance of the upper segment is lost
Clinical Features:
- Prolonged labour
- Irregular and painful Uterine contractions with marked low backache often in occipito-posterior position.
- High resting intrauterine pressure in between uterine contractions
- Slow cervical dilatation
- Premature rupture of membranes.
- Foetal and maternal distress
Management:
- Analgesic and antispasmodic as pethidine.
- Epidural analgesia
- Caesarean section
CONSTRICTION (Schroeder’s) RING:
- Persistent localised annular spasm of the circular uterine muscles.
- Occurs usually at junction of the upper and lower uterine segments.
- Occur at the 1st, 2nd or 3 rd stage of labour
Etiology:
- Malpresentations and malpositions.
- Clumsy intrauterine manipulations under light anaesthesia.
- Improper use of oxytocin(injudicious oxytocin )
Diagnosis:
- Common in Primigravidae and frequently preceded by colicky uterus.
- The exact diagnosis is achieved only by feeling the ring with a hand introduced into the uterine cavity
Complications:
- Prolonged 1st stage: Ring occurs at level of the internal os.
- Prolonged 2nd stage: If ring occurs around foetal neck.
- Retained placenta and postpartum haemorrhage: If ring occurs in 3rd stage (hour- glass contraction).
Management:
- 1st stage: Pethidine may be of benefit.
- 2nd stage: Deep GA and amyl nitrite inhalation are given to relax the constriction ring
- 3rd stage: Deep GA and amyl nitrite inhalation are given followed by manual removal of the placenta
CERVICAL DYSTOCIA:
- Failure of the cervix to dilate within a reasonable time in spite of good regular uterine contractions
Types:
- Organic (secondary):Cervical stances , cervical myoma or carcinoma.
- Functional (primary):external os fails to dilate.
Complications:
- Annular detachment of the cervix
- Rupture uterus
- Postpartum haemorrhage
Management:
- Organic :Caesarean section
- Functional : Pethidine and antispasmodic & CS
Exam Important
- Bandl’s ring is also called as Retraction ring
- Constriction ring Also called Schroeder’s ring
- Constriction ring Can be caused by injudicious oxytocin use
- Inhalation of amyl nitrate relaxes the Constriction ring
- Cervical dystocia is usually present at Level of external os
- Hypertonic dysfunctional labour is characterised by early Fetal distress
- Bandl’s ring is associated with Cephalopelvic disproportion
- Bandl’s ring is seen in Obstructed labour & Injudicious use of oxytocins
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