Abnormal uterine contraction

Abnormal uterine contraction

1. Abnormal uterine action Prepared by : Nirsuba Gurung Assistant Lecturer MSON

2. Normal uterine action Normal labour is characterized by coordinated uterine contractions(interval gradually shortens and intensity gradually increases) associated with progressive dilatation of the cervix ( Normal labour is associated with cervical dilatation ≥ 1cm \ hour in a nulliparous woman ) descent of the fetal head.

3. Polarity of uterus: When upper pole contracts lower pole relax Pacemakers : Two pace makers are situated at each cornua of the uterus generating contraction in co-ordinated manner Pattern of contraction : uterine contraction starts at cornua and propagate towards lower uterine segment with decrease in duration and intensity as it moves away from the pacemaker

4. Parameter of uterine action Basal tone : 5- 20 mm Hg Peak pressure : 60 -80 mm Hg Frequency of contraction :adequate uterine contractions are 1 in every 3 mints lasting for about 45 sec with good relaxation in between

5. Assessment of contraction Abdominal palpation Tocodynamometer :with the help of external trasducers Intrauterine pressure catheter

6. Abnormal uterine action Any deviation of the normal pattern of uterine contractions affecting the course of labour is designated as disordered or abnormal uterine action.

7. Overall labour abnormalities occur in about 25% of the nulliparous women and 10% of multiparous women.

8. Classification of abnormal uterine activity Inefficient uterine activity Hypoactive states/uterine inertia Hyperactive, incoordinate states Hyperactive lower uterine segment Colicky uterus Constriction ring Cervical dystocia Overefficient uterine activity Precipitate labour Tetanic uterine activity

9. ETIOLOGY   Prevalent in primi with advancing age of the mother   Prolonged pregnancy   Over distension of the uterus due to twins and or ployhydramnios Psychologic factor Contracted pelvis,  malpresentation and deflexed head. All these lead to ill fitting of the presenting part into the lower uterine segment. This probably results in inhibition of the local reflex which is needed to produce effective contraction of the upper segment.

10. Full bladder and loaded rectum reflexly inhibit uterine contraction Injudicious administration  of sedatives, analgesics and oxytocics Premature attempt at vaginal delivery or attempted instrumental vaginal delivery under light anaesthesia .

11. Uterine inertia Weak ,infrequent ,inefficient uterine action Uterine contraction: the intensity is diminished; duration is shortened; good relaxation in between contractions and the intervals are increased. General pattern of uterine contractions of labour is maintained but intrauterine pressure during contraction hardly rises above 25mm Hg

12. Etiology Elderly primi Anemia or other chronic illnes Hypertensive state in pregnancy Overdistension of uterus such as in twin or polyhydraminous Malpresentation and malposition Full bladder Uterine fibroid Premature induction of labour

13. Types Primary inertia :weak uterine contrations from the begining Secondary inertia : interia developed after a period of good contraction probably as the result of contracted pelvis as protective mechanism .

14. Sign and symptom 1.Patient feels less pain and discomfort during uterine contraction 2.Hand placed over the uterus during uterine contraction not only reveals hardening of the uterus before the patient feels pain but the contraction also outlasts the pain. 3.Uterine wall is easily indentable at the acme of a pain. 4.Uterus becomes relaxed after the contraction; fetal parts are well palpable and fetal hearts rate remains good.

15. Diagnosis    Internal examination reveals; Poor dilatation of the cervix Membranes usually remain intact Cervix well applied to the presenting part Associated presence of contracted pelvis,  malposition, deflexed head or malpresentation may be evident.

16. Complication Effect on mother: Prolonged labor Maternal distress, dehydration and psychological depression Increased risk for infection Increased risk of PPH Subinvolution

17. Fetal complication Fetal distress if membrane ruptures early

18. Management Careful evaluation of the case is to be done: To be sure that the patient is in true labour To exclude cephalopelvic disproportion or malpresentation To plan out the management protocol

19.   Detected in first stage: Place of caesarean section:   Presence of contracted pelvis Malpresentation Evidences of fetal or maternal distress        

20. Vaginal delivery General measures: To keep up the morale of the patient       To empty the bowel by enema and bladder by encouraging the patient to empty at intervals, failing which catheterization is to be done    To maintain nourishment by infusion of 5% dextrose Adequate sedation is ensured by intramuscular Pethidine 100 mg    

21. Active measures Acceleration of uterine contraction can be brought about by low rupture of the membranes followed by Oxytocin drip if not contraindicated. An infusion of 2 unit of Oxytocin     dissolved in 500ml 5% dextrose is started. The drip rate should be slow at first and is to be gradually increased until effective contractions are set up. Close watch of the maternal and fetal conditions and nature of uterine contractions is mandatory. The drip is to be continued till 1 hour after delivery; if, however, cervical dilatation remains unsatisfactory and \ or fetal distress appears, Caesarean section is the best alternative.

22. Detected in second stage   If the case is first seen at this stage, careful evaluation of the case is to be done to exclude contracted pelvis, malpresentation and to determine station of the head in relation to ischial spines and fetal condition.

23. Place of caesarean section   In presence of contracted pelvis or malpresentation where vaginal delivery is found unsafe and fetal condition remains good, caesarean section may be preferred even at this stage.

24. Vaginal delivery  Head low down – Forceps or ventouse delivery Head not sufficiently low down · Stimulation of uterine contraction by oxytocin drip or   Ventouse extraction. Difficult forceps should be avoided           Craniotomy – If the baby is   dead   

25. Third stage   Active management of the third stage is advocated

26. HYPERTONIC UTERINE ACTION  It is defined as either a series of single contractions lasting 2 minutes or more or a contraction frequency of five or more in 10 minutes.Uterine hyperstimulation may result in  fetal heart rate abnormalities ,  uterine rupture , or  placental abruption

27. Example Spastic lower uterine segment Colicky uterus Asymmetrical uterine contraction Constriction ring Generalised tonic contraction All these states are collectively called as incordinate uterine action

28. Inco-ordinate uterine action Strong and painful uterine contraction High frequency Slow cervical dilatation Two pole of uterus doesn’t functions rhythmically

29. Clinical feature Labour is prolonged. Uterine contractions are irregular and more painful. The pain is felt before and throughout the contractions with marked low backache often in occipito -posterior position. High resting intrauterine pressure in between uterine contractions detected by tocography (normal value is 5-10 mmHg). Slow cervical dilatation . Premature rupture of membranes. Foetal and maternal distress.

30. Management CPD- C/S Vital monitoring I/V therapy I/O charting FSH every 15 min Partograph Fetal distress-C/S

31. Colicky uterus Various parts of uterus contracts independently Hyperactive lower uterine segment Fundal gradient is lost , reverse gradient of the uterine activity starts from the lower uterine segment goes toward fundus and cervix

32. CONSTRICTION (CONTRACTION) RING It is a persistent localised annular spasm of the circular uterine muscles. It occurs at any part of the uterus but usually at junction of the upper and lower uterine segments. It can occur at the 1st, 2nd or 3 rd stage of labour .

33. Aetiology Unknown but the predisposing factors are: Malpresentations and malpositions . Premature rupture of membrane Premature attempt of instrumental delivery I ntrauterine manipulations under light anaesthesia . Improper use of oxytocin e.g. use of oxytocin in hypertonic inertia. IM injection of oxytocin .

34. Diagnosis 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. Complications 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).

35. Management Exclude malpresentations , malposition and disproportion. In the 1st stage: Pethidine m orphine may be of beneficial . 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

36. Pathological Retraction Ring ( Bandl’s ring) 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 .

37. 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 (see later). Obstructed labour should be properly treated otherwise the thinned lower uterine segment will rupture.

38. DIFFERENCE BETWEEN CONSTRICTION RING AND RETRACTION RING CONSTRICTION RING RETRACTION RING Nature It is a manifestation of localised inco-ordinated uterine contraction. It is an end result of tonic uterine contraction and retraction Cause Undue irritability of the uterus. Following obstructed labour Situation Usually at the junction of upper and lower segment but may occur in other places. The position does not alter.    At the junction of upper and lower segment. The position progressively moves upwards Uterus Upper segment contracts and retracts with relaxation in between lower segment remains thick and loose. Upper segment is tonically contracted with no relaxation The wall becomes thicker, lower segment becomes distended and thinned out

39. Maternal condition Almost unaffected unless the labour is prolonged    Maternal exhaustion, sepsis appear early Abdominal Examination o Uterus feels normal and not tender o Fetal parts are easily felt o FHS is usually felt o    Uterus is tense   and tender o    Not easily felt o    Ring is felt as a groove placed obliquely Vaginal examination o   The lower segment is not pressed by the presenting part o   Ring is felt usually above the head o   Features of obstructed labour are absent o Lower segment is very much pressed by the forcibly driven presenting part o Ring cannot be felt vaginally o Features are present End result o   Maternal exhaustion is a late feature o   Fetal anoxia usually appear late o   Chance of uterine rupture is absent o Maternal exhaustion and sepsis appear early o Fetal anoxia and even death are usually early o Rupture uterus in multi gravidae is common

40. Clinical feature Mother becomes tired and restless due to continue pain and discomfort Features of maternal distress and keto -acidosis Abdominal palpation Upper segment hard ,uniformly convex and tender Retraction ring obliquely placed between umblicus and symphysis pubis Fetal part may not be well defined FHS usually absent Vaginal examination Dry hot vagina with offensive discharge Cervix fully dilated Causes of obstruction is revealed

41. Management Provide supportive therapy Analgesic and sedation Hydration Prophylactic antibiotic Definitive treatment Destructive surgery if fetus is dead Fetus alive-C/S

42. CERVICAL DYSTOCIA Definition Failure of the cervix to dilate within a reasonable time in spite of good regular uterine contractions.

43. Types Organic (secondary) due to: Cervical stances as a sequel to previous amputation, cone biopsy, extensive cauterisation or obstetric trauma. Organic lesions as cervical myoma or carcinoma. Functional (primary): In spite of the absence of any organic lesion and the well 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 or excessive fibrous tissue .

44. Etiology Ineffective uterine contractions     Malpresentation , Malposition (abnormal relationship between the cervix and the presenting part)     Spasm (contractions) of the cervix

45. Management Organic dystocia : Caesarean section is the management of choice. Functional dystocia : Pethidine and antispasmodics: may be effective. Caesarean section: if medical treatment fails or foetal distress developed.

46. GENERALIZED TONIC CONTRACTION (UTERINE TETANY) In this condition pronounces retraction occurs involving whole of the uterus upto the level of internal os . Thus there is no physiological differentiation of the active upper segment and the passive lower segment of the uterus. As there is no thinning of the lower segment, there is no chance of rupture of the uterus. The uterine contraction ceases and the whole uterus undergoes a sort of tonic muscular spasm holding the fetus inside (active retention of the fetus)

47. Causes Failure to overcome the obstruction by powerful contractions of the uterus Injudicious administration of oxytocics Irritation caused by repeated unsuccessful attempt of instrumental delivery

48. Clinical Features The patient is in prolonged labor having severe and continuous pain. Abdominal examination revels the uterus to be somewhat smaller in size, tense and tender. Fetal parts are neither well defined, nor is the fetal heart sound audible. Vaginal examination reveals jammed head with big caput; dry and oedematous vagina.

49. Management Correction of dehydration and keto acidosis: by rapid infusion of Ringer’s solution Antibiotics : To control infection   Adequate pain relief