Normal and abnormal uterine action

Question 1

What are the 3 classifications for abnormal uterine action

Answer 1

Over-efficient uterus
*Precipitate delivery
*Excessive contraction and retraction
Inefficient uterine action
* Hypotonic inertia
* Hypertonic inertia
* Constriction (contraction) ring
Cervical dystocia

Question 2

What is precipitate delivery?

Answer 2

Precipitate delivery refers to a delivery which results after an unusually rapid labor (combined 1st stage and second stage duration is <2hrs) and culminates in the rapid, spontaneous expulsion of the infant.

Question 3

What are predisposing factors for precipitate labour

Answer 3

Multiparity 
Strong uterine contractions 
Small sized baby
Relaxed pelvic or perineal floor muscles
Roomy pelvis

Question 4

5 Maternal complications of precipitate labour?

Answer 4

Laceration
Hemorrhage from lacerations or hematoma 
Uterine atony from exhaustion
Infection
Uterine inversion

Question 5

4 Fetal complications of precipitate labour?

Answer 5

Intracranial hemorrhage from sudden change in pressure
Asphyxia - lack of resuscitation and placental compressions
Tearing of the umbilical cord
Fetal injury due to falling

Question 6

How do you manage precipitate labour

Answer 6

◦Hospitalize before due date
◦Inhalation anaesthesia: as nitrous oxide and oxygen is given to slow the course of labour.
◦Tocolytic agents.
◦Episiotomy to prevent lacerations
Examine for tears after

Question 7

What is retraction ring/Bandl’s ring in excessive contraction and retraction

Answer 7

It is the retraction ring that rises up 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.

Question 8

How does retraction ring/Bandl’s ring present?

Answer 8

Clinical picture: is that of obstructed labour with impending ruptured uterus

Question 9

How retraction ring/Bandl’s ring diagnosed?

Answer 9

The Bandl’s ring is seen and felt abdominally as a transverse groove that may rise to or above the umbilicus

Question 10

What is the complication of excessive contraction and retraction?

Answer 10

• In the pirmigravid woman, labour comes to a cease due to exhaustion of the muscles
• In multigravidae retraction continues with progressive thinning of the lower uterine which could cause rupture and hence foetal and maternal compromise

Question 11

How do you treat excessive contraction and retraction?

Answer 11

Adequate pain relief
Cesarean section
Prophylactic antibiotics

Question 12

What is hypotonic uterine action/inertia?

Answer 12

The uterine contractions are infrequent, weak and of short duration

Question 13

What are general predisposing factors for hypotonic uterine action

Answer 13

• Primigravida particularly elderly
• Anaemia and asthenia
• Nervous and emotional as anxiety and fear.
• Hormonal due to deficient prostaglandins or oxytocin as in induced labour
• Improperuseofanalgesics

Question 14

What are local factors of hypotonic uterine action

Answer 14

• Overdistension of the uterus.
• Developmental anomalies of the uterus e.g. hypoplasia.
• Myomas
• Malpresentation

Question 15

How do you manage hypotonic uterine action

Answer 15

Induction of labour - oxytocin, amniotomy
VD with instrumentation
Cesarean section if SVD fail, contraindication to oxytocin, fetal distress

Question 16

What is hypertonic uterine action/inertia?

Answer 16

Uncoordinated uterine action

Question 17

What are the 2 types of hypertonic uterine inertia?

Answer 17

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

Question 18

What is the presentation of hypertonic uterine action?

Answer 18

Prolonged labour
More painful and irregular contraction. The pain is felt before and throughout the contractions with marked lower backache.
High resting intrauterine pressure in between uterine contractions detected by tocography
Slow cervical dilatation
Premature rupture of membranes.
Foetal and maternal distress

Question 19

How do you manage hypertonic uterine action

Answer 19

Pharmacotherapy:
o Analgesic.
o Epidural analgesia may be of good benefit. 

Caesarean section is indicated in:
o Failure of the previous methods.
o Disproportion.
o Foetal distress before full cervical dilatation

Question 20

What are constriction rings / contraction rings / Schroeder’s rings

Answer 20

It is a persistent localised annular spasm of the circular uterine muscles that occurs at any part of the uterus but usually at junction of the upper and lower uterine segments and may appear at any stage during labour

Question 21

What are some associated factors of constriction rings / contraction rings / Schroeder’s rings

Answer 21

Mal-presentations and mal-positions.
Improper use of oxytocin e.g.
◦ use of oxytocin in hypertonic inertia.
◦ IM injection of oxytocin
Premature rupture of membrane
Premature attempt in instrumental delivery

Question 22

How do you diagnose constriction rings / contraction rings / Schroeder’s rings

Answer 22

The condition is more 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.

Question 23

What are 3 possible complications of constriction rings / contraction rings / Schroeder’s rings

Answer 23

Prolonged 1st stage: if the ring occurs at the level of the internal os.
Prolonged 2nd stage: if the ring occurs around the foetal neck.
Retained placenta and postpartum haemorrhage: if the ring occurs in the 3rd stage (hour- glass contraction).

Question 24

How do you manage constriction rings / contraction rings / Schroeder’s rings

Answer 24

• In the 1st stage: Pethidine may be of benefit.
• In the 2nd stage: Deep general anaesthesia and amyl nitrite inhalation are given to relax the constriction ring:
  ◦ If the ring is relaxed, the foetus is delivered immediately by forceps.
  ◦ If the ring does not relax, caesarean section is carried out with lower segment vertical incision to divide the ring.
• In the 3rd stage: Deep general anaesthesia and amyl nitrite inhalation are given followed by manual removal of the placenta

Question 25

Differences between a constriction ring and a retraction ring

Answer 25

Check evernote

Question 26

What is cervical dystocia

Answer 26

Failure of the cervix to dilate within a reasonable time in spite of good regular uterine contractions

Question 27

What are the 2 types of cervical dystocia? (just state)

Answer 27

Primary (functional) and secondary (organic)

Question 28

What is primary (functional) cervical dystocia?

Answer 28

• In spite of the absence of any organic lesion and the good effacement of the cervix, the external os fails to dilate.
• This may be due to lack of softening of the cervix during pregnancy or cervical spasm resulted from overactive sympathetic tone

Question 29

What is secondary (organic) cervical dystocia?

Answer 29

• Excessive scarring or rigidity of cervix post previous operation, disease or delivery eg previous amputation, cone biopsy, extensive cauterization or obstetric trauma.
• Organic lesions as cervical myoma or carcinoma.

Question 30

What are 3 complications of cervical dystocia?

Answer 30

1 - Annular detachment of the cervix: surprisingly the bleeding from the cervix is minimal because of fibrosis and avascular pressure necrosis leading to thrombosis of the vessels before detachment.
2 - Rupture uterus secondary to prolonged labour and obstruction
3 - Postpartum haemorrhage: particularly if cervical laceration extends upwards tearing the main uterine vessels.

Question 31

How do you manage primary cervical dystocia (functional)?

Answer 31

Pethidine and antispasmodics: may be effective.
Caesarean section: if
* medical treatment fails or
* foetal distress developed

Question 32

How do you manage secondary cervical dystocia (organic)?

Answer 32

Caesarean section is the management of choice