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—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—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.