LABOR AND ITS STAGES

OBSTERTRICS AND GYNAECOLOGY

1. LABOR AND ITS STAGES SHALINI SHANMUGAM FINAL YEAR MBBS

2. LABOR - DEFINITION Labor is the process by which products of conception are expelled by the mother after period of viability either spontaneously or with the external aid to complete it. Spontaneous expulsion of the products of conception before the period of viability of the foetus is termed ABORTION OR MISCARRIAGE

3. STAGES OF LABOR STAGES OF LABOR

4. 1ST STAGE Begins with onset of true labor pain to full dilatation of cervix. 1 st STAGE LATENT PHASE ACTIVE PHASE

5. LATENT PHASE STARTS WITH TRUE LABOR PAIN TO 5CM DILATATION OF CERVIX. MAIN ACTIONS OF THE LATENT PHASE 1.DILATATION OF CERVIX 2.EFFACEMENT OF CERVIX MUCOSANGUINOUS DISCHARGE Is the evidence of cervical dilatation and effacement. A small amount of red tinged mucus is passed which is called the SHOW.

6. DURATION UPPER LIMIT OF NORMAL AVERAGE DURATION PRIMIGRAVIDA 20 HOURS 12 HOURS MULTIGRAVIDA 14 HOURS 8 HOURS

7. IN A NON PREGNANT FEMALE ISTHMUS IS 5cm, in pregnancy this enlarges ,becomes 5cm and forms the lower uterine segment IN A PREGNANT FEMALE THE LENGTH OF THE CERVIX IS 4-5 CM. CONSIDERING THE ISTHMUS LENGTH AND 100% CERVIX EFFACEMENT THE LENGTH OF THE LOWER UTERINE SEGMENT BECOMES 10CM

8. ACTIVE PHASE From 6 cm dilatation of cervix till end of first stage i.e complete 10cm dilatation of cervix Minimum rate of cervical dilatation -1cm/hr( avg ) primi gravida-1.2cm/hr multigravida-1.5cm/hr Bag of membrane rupture

9. SECOND STAGE BEGINS WITH FULL DILATATION OF CERVIX AND ENDS WITH THE DELIVERY OF THE FOETUS. IN CASE OF EPIDURAL ANAESTHESIA , THE NORMAL LIMITS WILL BE PROLONGES BY 1 HOUR.

10. SECOND STAGE Second stage or the STAGE OF EXPULSION extends from the complete dilatation of the cervix to the expulsion of the foetus or foetuses. This stage may last from one or two hrs in a primigravida and from half to one hr in a multipara. The nature of uterine contractions gradually changes getting stronger IN THE SECOND STAGE. They are more severe than in the first stage and are of a BEARING DOWN CHARACTER. The voluntary muscles- the accessory muscles of labor also begin to contract and exert their influence towards the end of the second stage. The diaphragm and the abdominal muscles begin to act. With each of these pains, the foetus is pushed down through the dilated cervical canal , and the vagina relaxes and dilates to receive it. When the perineum is reached ,it is stretched so that it begins to bulge with each uterine contraction.

11. The vulva begins to widen when the presenting part is fixed under the symphysis pubis the phenomenon known as CROWNING OF THE HEAD-in vertex presentations At this stage , the patient feels an inclination to micturate and defecate. This is due to the pressure of the presenting part on the bladder and rectum. Lastly , the head passes through the outlet with a series of almost continuous uterine contractions ,helped by involuntary straining efforts on the part of the patient , due to the action of the accessory muscles of labour. As the expulsion of the head takes place , the patient exerts one last effort , and thereafter the rest of the FOETUS IS BORN.

12. THIRD STAGE OF LABOR BEGINS WITH THE DELIVRY OF THE FOETUS TO DELIVERY OF PLACENTA UPPER LIMIT OF NORMAL IS 30 MINS AVERAGE DURATION IS 15 MINS FURTHER DECREASE IN DURATION CAN BE ACHIEVED WITH ACTIVE MANAGEMENT

13. THIRD STAGE OF LABOR The third stage or the STAGE OF PLACENTAL DELIVERY is very important and should be carefully watched. This extends from the complete expulsion of the foetus to the complex expulsion of the placenta and membranes and firm contraction and retraction of the uterus subsequently. The average duration of this stage ,when spontaneously completed , may extend from a few minutes to fifteen minutes.

14. The phenomena of the third stage of labor are 1.characteristic uterine contractions 2.Separation of the placenta 3.Expulsion of the placenta 4.Control of haemorrhage 5.Permanent contraction and retraction of the uterus

15. UTERINE CONTRACTION After the completion of the second stage , the uterus will be found almost at the level of the umbilicus , and will be firm , round and hard. Rhythmic contractions occur and the patient may sometimes feel the pain.

16. PLACENTAL DETACHMENT As the foetus is being delivered , the separation of the placenta may take place. The shrinkage of the placental site and the forcing downward of the whole placental mass by uterine contraction may cause the separation.

17. The two methods by which placental expulsion may occur are : DUNCAN’S METHOD : On account of the contractions of the uterus, the placenta may be folded on itself , so that the long axis of the placenta corresponds to the long axis of the uterus and the margin that presents at the cervix or vagina is the lower margin , showing perhaps a little of the fetal surface

18. SCHULTZE’S METHOD : Here the placenta may separate at it centre. A retroplacental heatoma is formed which with each contraction of the uterus , forces more of the placenta to separate and the placenta thus separated presents itself at the vaginal outlet,with the cetre of its fetal surface with the attached cord,like an inverted umbrella. It is of little significance which method of expulsion is responsible for its final delivery.

19. EXPULSION OF THE PLACENTA This usually occurs within a few minutes after the birth of the foetus. During this period , the uterus should be moderately hard in terms of tonicity , so that when the placenta separates , the contractions and retractions of the uterus will arrest haemorrhage by closure of the placental sinuses.

20. CONTROL OF HEMORRHAGE After the separation of the placenta , control of haemorrhage is due to three factors. 1.Contraction and retraction of the uterus , constricting the vessels passing through the uterine wall to the placental site. 2.occlusion of the torn vessels themselves. 3.Formation of blood clots which favour the closure of the lumen of the vessels. During the third stage and immediately after , there is always a moderate amount of bleeding in a normal patient , it does not exceed 250ml. When labor is over , the patient may occasionally have an episode of rigour , which is a purely vasomotor phenomenon and is not indicative of infection , and is generally of no particular significance. It is termed PHYSIOLOGICAL CHILL APYREXIAL SHIVERING.

21. FOURTH STAGE OF LABOR 1 HOUR OBSERVATION PERIOD AFTER THE DELIVERY OF THE PLACENTA . PATIENT WILL EXPERIENCE PHYSIOLOGICAL CHILLS. USUAL TIME FOR THE RUPTURE OF THE BAG OF MEMBRANES IS AT THE END OF 1 ST STAGE OF LABOR.

22. CEPHALOPELVIC DISPROPORTION CPD When the pelvis is contracted or cephalopelvic disproportion is such that delivery of a live child per vaginum is not possible, elective caesarean section is the treatment of choice. In borderline pelvis and minor degrees of disproportion , trial of labor may be given. When trial of labor fails , caesarean section becomes necessary to deliver a live child. In spite of safety rendered to caesarean section under modern conditions , maternal mortality and morbidity will increase with the duration of labor , especially after rupture of the membranes. Hence for the best results , the patients should be carefully selected and undue prolongation of labor should be avoided.

23. CPD – CONTRACTED PELVIS Alteration in size and or shape of the pelvis of sufficient degree to alter the normal mechanism of labor in an average sized baby. CEPHALOPELVIC DISPRPORTION IS BEST ASSESSED ONLY AT THE ONSET OF LABOR.

24. VARIOUS METHODS TO ASSESS CPD Clinical assessment of pelvis Imaging pelvimetry Assessment of foetal height

25. PRE REQUISITES FOR ASSESSING CPD Explain to the patient about the procedure. Bladder should be empty Patient should be in dorsal position Done under aseptic precautions. Internal procedures should be gentle. Pelvic capacity can be estimated clinically by evaluating various measurements with the middle and index finger of right hand during bimanual examination.

26. Clinical methods of diagnosing CPD ABDOMNAL METHOD IAN DONALD METHOD ABDOMINO PELVIC ASSESSMENT BY MUNRO KERR – MULLER METHOD CLINICAL PELVIMETRY

27. IAN DONALD METHOD

28. ABDOMNAL METHOD CLINICAL PELVIMETRY

29. ABDOMINO PELVIC ASSESMENT BY MUNRO KERR-MULLER METHOD MUNRO KERR described that thumb is to be placed over the pubic symphysis. MULLER described that the middle and index fInger of right hand are to be placed at ischial spines , to find out whether head can be pushed up to the level of ischial spines. Procedure : after emptying the bladder , woman is placed in dorsal position with thigh and knee semi flexed. Obstetrician stands on the right side facing her and grasps the foetal head with the left hand and pushes it into pelvis brim , while middle and index fingers of right hand are kept at the level of ischial spine and thumb of the right hand is kept over the pubic symphysis.

30. MUNRO KERR-MULLER METHOD

31. INTERPRETATION When the head can be pushed up to ischial spines and no overlapping of parietal bone occurs over the pubic symphysis- NO CPD Head can be pushed little but not up to ischial spines and parietal bne is flsh with pubic symphysis- MILD DEGREE CPD Had cannot be pushed down and there is overriding of the parietal bone over pubic symphysis- MAJOR DEGREE CPD Pitfall in the procedure-it can assess only contraction at the brim.

32. ABDOMINAL METHOD The patient is placed in dorsal position with the thighs slightly flexed and separated. The head is grasped by the left hand. Two fingers ( index and middle ) of the right hand are placed above the symphysis pubis keeping the inner surface of the fingers in limne with the anterior surface of the symphysis pubis to note the degree of overlapping , if any , when the head is pushed downwards and backwards.

33. INFERENCES The head can be pushed down in the pelvis without overlapping of the parietal bone on the symphysis pubis- NO DISPROPORTION Head can be pushed down a little but there is slight overlapping of the parietal bone evidenced by touch on the undersurface of the fingers (overlapping by 0.5 cmor ¼ which is thethckness of the symphysis pubis ) – MODERATE DISPROPORTION Head cannot be pushed down and instead the parietal bone overhangs the symphysis pubis displacing the fingers – SEVERE DISPROPORTION

34. THE ABDOMINAL METHOD CAN BE USED AS A SCREENING PROCEDURE. At times it is difficult to elicit due to deflexed head , thick abdominal wall , irritable uterus and high floating head.

35. RESPECT WOMEN !!!!

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