Managing an obstructed labour

If a patient with obstructed labour is admitted from home, she may have been in labour for days, and tried many home remedies. Her stomach is likely to be full, and she can inhale its contents only too easily. She is thus a major anaesthestic risk. There are several ways in which you can deliver her, but the standard midcavity or rotational forceps, such as Kielland's, should never be one of them (18.1).

Vaginal delivery is often possible, but try to avoid a difficult one. Learn to predict when it is going to be difficult, so that you can avoid a ''failed vacuum', and do a Caesarean section or a symphysiotomy (18.6, M 22.7) to begin with, especially when there is fetal distress. An operative vaginal delivery is absolutely contraindicated if her uterus has already ruptured[md]do a laparotomy. Often, you will not know if it has ruptured or not, so do all vaginal operations for the relief of obstructed labour in the theatre, with a set of laparotomy instruments ready for instant use.

Caesarean section has a limited role, and is likely to be a serious risk, so don't do it lightly. It is mainly indicated: (1) when a baby is alive and his mother is in reasonable condition. (2) When a destructive operation on a dead baby would be dangerous, because his head is mobile 3/5, or more, high above her pelvic brim (rare). Try not to section her, if she cannot be sure of adequate care in her next delivery, or if your skills and facilities for doing so safely are not good. If you have to section her, Section 18.8 will help you to decide on the most suitable method.

A destructive operation (M 22.10) is indicated when her baby is dead, her cervix is fully dilated or nearly so, the presenting part is fixed in her pelvis, and her uterus has not ruptured, and is in no danger of doing so. Usually, you can be fairly sure that a uterus is not going to rupture. If you are in any doubt, the only way to find out is to do a laparotomy, and see if there is a rupture. If you don't find one, close her abdomen and deliver her vaginally.

OBSTRUCTED LABOUR A mother in obstructed labour is in great pain, anxiety, and distress. In the bustle of treating her, don't forget to comfort 8and reassure her. If her baby is already dead, tell her. If you don't, she may blame you for his death, and not come to hospital when she is pregnant next time. Many of the steps and complications are the same as for rupture of the uterus, so see Section 18.17.

THE DIAGNOSIS. Suspect obstructed labour when: (1) Her cervix does not dilate in spite of good contractions. (2) Moulding and caput increase, but her baby's head does not descend. (3) She becomes anxious and restless. (4) She develops hypertonic uterine contractions, with poor relaxation between them. Other signs are: (5) A stretched lower segment. (6) Bloody urine. (7) Unexpectedly easy dislodgement of the presenting part followed by a gush of vaginal bleeding[md]abandon vaginal delivery and open her abdomen. (8) A cervix which is not well applied to the head (variable).

An important differential diagnosis is a prolonged latent phase without obstruction. If she was made to push during the latent phase, she may be distressed and dehydrated, and her vulva and cervix may be oedematous. Her cervix will however not be dilated, or only slightly so, her membranes are likely to be intact, and there will be no Bandl's ring. Reassurance, analgesics, and fluids may be all she needs.

The diagnosis of obstruction is certain if: (1) Bandl's ring (18-3) is present, or (2) she has a bladder fistula or necrosis. This takes 2 or 3 days to develop, so it is rare for her to present with one.

When you diagnose obstructed labour, the next critical question is: has her uterus already ruptured? To answer this, see Section 18.17 on rupture of the uterus. If it has not ruptured, proceed as follows:

HYPOVOLAEMIC SHOCK (very common). Resuscitation must be rapid, because delivery is urgent. Admit her directly to whatever high-risk area you have, usually the labour ward or the theatre, and resuscitate her there. This will allow you to operate as soon as she is in an optimal condition.

Correct her dehydration, her electrolyte deficit, and her acidosis (A 17.2). Rehydrate her with 0.9% saline or Ringer's lactate, and continue with dextrose 5%; there is usually no need to give her bicarbonate. She may need blood, preferably the red cells only. If her haematocrit is raised as the result of ]]dehydration, a transfusion, even of safe blood, may be harmful[md]she needs fluids.

If possible, set up a central venous line and measure her CVP (A 19.2). If this is within the range of 5 to 8 cm of water, and she is still shocked, at least part of her problem is likely to be septic shock exacerbated by ketosis.

Record her pulse, her blood pressure, and her CVP every five minutes during the operation. Monitor her urine output regularly. If it falls to less than 30 ml/hour, see Section 53.3.

SEPTIC SHOCK (less common). If she is ill and weak, but not actually in septic shock (53.4), she probably soon will be, if you don't prevent it. So start the following regime prophylactically.

Give her intravenous chloramphenicol and intravenous or rectal metronidazole (2.9). If, in spite of this, her blood pressure remains low, her urinary output is poor, and her vessels remain constricted, she needs a titrated infusion of dopamine (53.4). This will cause peripheral dilatation, and a fall in her CVP. Correct it immediately with more intravenous fluids.

ANAESTHESIA. If she is to have a Caesarean section, see Section A 16.6. If she is to be delivered vaginally, use a pudendal block (18.2, A 6.13), a saddle block (A 7.7), or an epidural block (A 7.3). Remember to insert a nasogastric tube.

[+15]METHODS OF DELIVERY [s7]WHEN THE PRESENTING PART HAS STOPPED DESCENDING When the presenting part has stopped descending, her cervix will probably also have stopped dilating (her ''progress line' will have crossed the ''action line' on her cervicograph), although it may continue to in multips. You will probably find the following summary one of the most useful sections in this manual, since it is the key to this chapter. It covers a variety of situations in which the presenting part no longer descends in the birth canal. In some of them, the classical signs of obstructed labour (severe moulding, etc.) have yet to occur, so it is a combination of methods for the management of delay and obstruction. First the various methods are considered (episiotomy, etc.), and then the various clinical situations you might meet. Before you continue, you will need to:

Assess the height of the baby's head (M 18.4). Don't assess the height of his head by vaginal examination only. There will be much caput, and this will mislead you. It is the descent of his skull that matters, not the descent of his caput!

Assess his moulding score (18.6). Feel where his parietal and occipital bones touch one another. Bones still separate, score 0. Bones touching, score 1. Bones overlapping, but separate when you press with a finger, score 2. Bones overlapping but not separable, score 3. Overlapping at both the sagittal and the lambdoid sutures, is more serious than overlapping at the lambdoid suture only (this is the suture between the parietal and the occipital bones).

Watch for fetal distress. Count his heart rate for 30 seconds, before, during and after a contraction. Fetal distress is shown by: (1) A rate of [lt]120 or [mt]160. (2) Slowing which persists after a contraction (slowing during it is normal).

CAUTION ! (1) Don't use an oxytocin drip if there are signs of obstruction. On the correct indications, you can use it for delay (18.4a). (2) If there is obstruction or delay, don't use Kielland's forceps, or try internal version. (3) Never do an operative vaginal delivery if her uterus has already ruptured[md]do a laparotomy. You may not know if it is ruptured or not, so do all vaginal operations for the relief of obstructed labour in the theatre, with a set of laparotomy instruments ready for instant use.

EPISIOTOMY [s7]M 18.16 This is sometimes all that a primigravida needs, especially if her baby's vertex is in an occipito[nd]posterior position. Putting her into the lithotomy position may make delivery easier.

VACUUM EXTRACTION [s7]18.5, M 22.3 INDICATIONS. (1) A live baby with less than 2/5 of his head above the brim. And, (2) only moderate moulding. Vacuum extraction may be very suitable, if obstruction is due to an occipito-transverse or an occipito-posterior position, without CPD, or with only mild CPD.

CONTRAINDICATIONS. (1) A dead baby, unless delivery by vacuum extraction is very easy. (2) A live baby with more than 2/5 of his head above the brim. (3) Severe moulding. (4) Definite CPD contraindicates any kind of forceps or vacuum extraction.

CAUTION ! (1) Delivery with a vacuum extractor or outlet forceps should never be a difficult operation. If fetal asphyxia is already present, it should merely be a ''lift-out'. (2) If you use the vacuum extractor, be sure to follow the rule of the ''Three pulls' (M 22.3). The first pull must dislodge his head from its arrested position, the second must bring his head to the pelvic floor, and the third must deliver, or at least crown it. If any one of these three pulls does not achieve its purpose, stop, and try another method of delivery. This will have to be symphysiotomy or section, and not forceps, which are too dangerous for a baby after a failed vacuum. If possible, try to predict difficulty, and choose the right method in the first place. (3) If (a) she was [mt]3 hrs dilating from 7 to 10 cm on the partogram, or (b) her fundal height is [mt]40 cm, suggesting a large baby, expect difficulty. Do the vacuum extraction in the theatre, and prepare for section.

OUTLET FORCEPS [s7]M 22.6 INDICATIONS. (1) In mento[nd]anterior (face) presentations, because vacuum extraction is impossible (M 22.6). One contributor considers section safer. (2) When there is fetal distress, because outlet forceps are quicker than vacuum extraction.

SYMPHYSIOTOMY [s7]18.6, M 20.7 INDICATIONS. Symphysiotomy may be indicated if a baby is alive in a cephalic presentation, with not more than 2/5, or in some cases (see Section 18.6) 3/5, of his head above the brim. He should not be too big, or too small (2.5 to 4 kg), and his moulding score should be less than 3. An indication of his maximum size is that her fundal height should be [lt]40 cm.

DESTRUCTIVE OPERATIONS [s7]18.7, 18.10 INDICATIONS FOR CRANIOTOMY. All the following conditions must hold: (1) He must be dead. (2) 2/5 or less of his head must be above the brim (if it is higher than this, Caesarean section is usually safer, although if you are expert you may be able to do a craniotomy at 3/5). (3) His head must be impacted. (4) His mother's cervix must be at least 7 cm dilated, and preferably fully dilated. (5) Her uterus must be unruptured, and not in imminent danger of rupturing. If she is a multip, and has been in labour for a long time, her lower segment will be very thin. If it is tender and distended, it is certainly very thin. She can only be saved by Caesarean section; any destructive operation, except pushing a needle into a hydrocephalic head, will rupture it.

INDICATIONS FOR DESTRUCTIVE OPERATIONS FOR A TRANSVERSE LIE. The baby is dead and is lying transversely, her cervix is 8 cm or more dilated, and her uterus is not ruptured.

CAESAREAN SECTION [s7]18.9 INDICATIONS. (1) A live baby whose head is too high for vacuum extraction or symphysiotomy. (2) A dead baby who is too high to be delivered by a destructive operation (rare).

CONTRAINDICATIONS. (1) A head which is deeply engaged in the pelvis (2/5 or less above the brim). A vaginal delivery by vacuum extraction or symphysiotomy is safer. (2) A dead baby who can be delivered by a destructive operation.

Fig. 18-4 CHOOSING THE BEST METHOD TO DELIVER A MOTHER WITH A LONG SECOND STAGE AND A LIVE BABY. This is a table from ''Primary Mother Care' which advises midwives what they should do in health centres. You may also find it useful. It differs slightly from the instructions for similar situations given here. Kindly contributed by Hugh Philpott.

CLINICAL SITUATIONS [s7]WHEN THE PRESENTING PART HAS STOPPED DESCENDING Here we are mostly concerned with a vertex presentation, and a few curiosities. See elsewhere for a breech presentation (19.8), a transverse lie, and a brow or a face presentation (19.9).

VERTEX PRESENTATION. Follow this scheme.

If rupture is suspected but uncertain, section her.

If her baby is alive and her cervix is not fully dilated, section her.

If he is alive and it is fully dilated, management depends on: (1) the height of his head, (2) the degree of moulding, and (3) signs of fetal distress.

0/5 above the brim, with minimal moulding[md]do an episiotomy and apply the vacuum extractor, or apply outlet forceps.

1/5 above the brim, with a moulding score of 0 to 1 and fetal distress[md]do a vacuum extraction or apply outlet forceps.

1/5 above the brim, with a moulding score of 2 or 3 and fetal distress[md]do a symphysiotomy.

2/5 above the brim, with a moulding score of 0 or 1 or possibly 2 and a live baby[md]do a trial of vacuum extraction in the theatre, with everything ready for symphysiotomy or section if you fail. Or section her anyway.

2/5 above the brim, with a moulding score of 3 or possibly 2 and fetal distress[md]do a symphysiotomy, if necessary followed by vacuum extraction.

3/5 above the brim, with a moulding score of 0 or 1[md]do a trial of vacuum extraction. If necessary and her pelvis is big enough (you can get your finger between the head and her symphysis) do a symphysiotomy.

3/5 above the brim, with a moulding score of 2 or 3[md]section her, unless you can get a finger between the head and her pelvic wall, indicating that a symphysiotomy might be possible.

If he is dead, the major decision is between craniotomy and Caesarean section.

(1) If his head is firmly impacted in her pelvis, and his head is 2/5 or 3/5 or less above the brim, and her cervix is 7 cm or more dilated, a craniotomy should be fairly easy, provided you can get a finger between his head and her pelvis.

(2) If his head is mobile or more than 3/5 above the brim, a craniotomy will be dangerous. Section, with all its risks, will be safer.

A MENTO[nd]POSTERIOR PRESENTATION. If her cervix is fully dilated and her baby is alive, section her. If he is dead, and her cervix is fully dilated, do a craniotomy.

A CONGENITAL VAGINAL SEPTUM (rare) seldom causes trouble, because it usually quite thin, pushes to one side, and may never even be diagnosed during labour. If it does cause trouble, but is thin, you may be able to divide it. If it is thick, you may have to section her, and excise it later when she is not pregnant.

A VAGINAL STRICTURE (quite common) caused by scar tissue from a previous delivery, or of uncertain cause, feels quite different from a cervix. If it is thin, incise it at 4 o'clock and 8 o'clock, let vaginal delivery proceed, and suture the laceration. If it is wide and fibrous, section her.

AN OVARIAN TUMOUR OR A FIBROID. Section her. If she has an ovarian cyst or tumour, you can remove it at Caesarean section. If she has a fibroid, leave it and remove it subsequently if necessary.

CAUTION ! Never try to remove a fibroid at Caesarean section.

POSTOPERATIVELY [s7]AFTER A DIFFICULT VAGINAL DELIVERY Keep her in hospital for three or four days (14 days for a symphysiotomy). Observe her carefully. Before she goes home, make sure that she understands: (1) what operation she had, and (2) why it was done. This will be important when she becomes pregnant again.

Her baby has a greater chance of brain damage. This may be caused by: (1) The operation itself. (2) Lack of oxygen. (3) Her pelvis being too small for his head. Watch him carefully for signs of twitching, irritability, or fever.

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If she has had an obstructed labour examine her early in the puerperium for signs of peripheral nerve injury. She may fail to complain about sensorychanges and weakness, so youwill have to look for them[md]se below. Put her on an accurate fluid balance chart and watch for renal failure. This is serious, but potentially curable. Early treatment will improve her prognosis, so watch for it. See Section. If she has had large amounts of fluids and is out of shock and yet passes [lt]400 ml of fluid in24 hourss, she is in renal failure[md]see below. DIFICULTIES [s7]WITH OBSTRUCTED LABOUR See also... If she is in RENAL FAILURE, try frusemide 100[nd]500 mg intravenously. If this fails try dopamine 1 [gm]g/kg/minute. If this fails fluid intake against fluid loss as in Section... Se also Lawson and Stewart. If she has SENSORY CHANGES and WEAKNESS in her legs, she has an OBSTETRIC PARALYSIS, which may vary from mild footdrop to extensive paralysis of her legs, including her glutealand quadriceps muscles. If you are not carefuly, she may develop contractures. So put her lets through their full range of passive movements regularly, and encourage her relatives to do the same. If she has foot drop, give her a posterior plaster splint to keep her ankle at 90[de] at night. She is almost certain to recover, but this may take 2 years.

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Fig. 18-5 TWO TUMOURS OBSTRUCTING LABOUR. A, an ovarian cyst. B, a cervical fibroid. If a patient has an ovarian cyst or tumour, you can remove it at Caesarean section. If she has a fibroid, leave it and remove it later if necessary. After Young, James, ''A Textbook of Gynaecology' (5th edn. 1939), Figs. 125 and 168. A and C Black. surg74