METHODS OF DELIVERY 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 <120 or >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—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 M 18.16

This is sometimes all that a primigravida needs, especially if her baby’s vertex is in an occipito–posterior position. Putting her into the lithotomy position may make delivery easier.

VACUUM EXTRACTION 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 >3 hrs dilating from 7 to 10 cm on the partogram, or (b) her fundal height is >40 cm, suggesting a large baby, expect difficulty. Do the vacuum extraction in the theatre, and prepare for section.

OUTLET FORCEPS M 22.6

INDICATIONS. (1) In mento–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 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 <40 cm.

DESTRUCTIVE OPERATIONS 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 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.

CLINICAL SITUATIONS 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—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—do a vacuum extraction or apply outlet forceps.

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

2/5 above the brim, with a moulding score of 0 or 1 or possibly 2 and a live baby—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—do a symphysiotomy, if necessary followed by vacuum extraction.

3/5 above the brim, with a moulding score of 0 or 1—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—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–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 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.