More malpresentations

A transverse lie occurs most frequently in multips, and in mothers with polyhydramnios. When you diagnose it, don't forget the possibility that it may have been caused by twins, a major degree of placenta praevia, or CPD. Rarer causes include a congenital uterine abnormality, a grossly abnormal pelvic brim, a fibroid, an ovarian tumour, and an extrauterine pregnancy. When labour is obstructed by a transverse lie, the lower segment is particularly vulnerable, so don't stretch it any more by doing an internal version in advanced labour with a dead baby. Do a destructive operation (18.7).

MORE MALPRESENTATIONS TRANSVERSE LIE If a patient is 32 weeks pregnant or more, do an external cephalic version (19.8). This is safe provided there is no antepartum haemorrhage, hypertension with a blood pressure of [mt]100 mm, or twins. If you fail, try again a week later. See also M 19.2. For obstructed labour with a transverse lie, see Sections 18.4 and 18.7 (destructive operations). For a transverse lie with twins see Section 19.11.

If she goes into labour with a transverse lie, when she is less than 30 weeks, or her baby feels as if he is under 1.5 kg, she may deliver spontaneously, although he is unlikely to survive. She also runs an increased risk of prolapse of the cord.

If you see her in the latent phase of labour, when she still has intact membranes and uterine contractions which are not strong, do an external version to produce a cephalic presentation. If this is successful, and she has no signs of CPD, and the position is still unstable, rupture her membranes while an assistant holds her baby's head over her pelvis. If she is of low parity, start an oxytocin drip (M 22.2). Check his lie and fetal heartbeat every 15 minutes, until his head is fixed in her pelvic brim.

If she has a small pelvis with an estimated true conjugate of [lt]9 cm, section her.

If he is alive and she is in the active phase of labour with intact or ruptured membranes, and her cervix is [lt]8 cm, section her. If her membranes are still intact, and you can feel a leg through her lower segment, you can deliver him through a lower segment transverse incision. But if her membranes have ruptured, and especially if his arm has prolapsed, a de Lee incision (18.9) is better, because you can extend this into the upper segment as necessary.

If he is alive and she is fully dilated or nearly so: (1) If she is a primip or a multip with a tight uterus, section her. (2) If she is a multip with intact membranes, and a uterus which is not tight, an internal version and breech extraction is sometimes advised. It is however very dangerous, and at least one contributor considers that the only indication for this manoeuvre is the transverse lie of a second twin with intact membranes (19.11).

If he is dead, and her cervix is not yet 8 cm dilated, do a lower segment section, and a transabdominal destructive operation. Use large scissors to decapitate him through the uterine incision (18.9, 18.10).

If he is dead, with an impacted shoulder, and her cervix is [mt]8 cm dilated, and her uterus is not ruptured, do a destructive operation (18.7).

A BROW PRESENTATION A brow presentation is often missed: (1) During labour. The head is high, but by the time it comes lower, the sutures and fontanelles by which it might have been diagnosed, have become obscured by caput. (2) At Caesarean section a brow presentation is not diagnosed until the typical moulding makes the diagnosis obvious. Unless the baby is premature, or his mother's pelvis is enormous, he will not deliver vaginally.

If you diagnose a brow presentation and she is early in labour, her pelvis is large, and he is of normal size, his head may flex, and he may deliver vaginally. You may be able to assist flexion by putting your hand through her cervix, pushing his head up and trying to flex it. But, if you fail to flex his head, if her membranes rupture, or if she fails to progress, or if there is any sign of obstruction, section her.

A FACE PRESENTATION If her pelvis is large and there are no signs of CPD, allow her labour to progress. He is most likely to be mento-lateral, and will probably rotate anteriorly and deliver spontaneously. You may be able to help by turning him with your hand. If he remains mento-posterior, you will have to section her.

If she is delayed in the second stage and he is in the mento-anterior position, with less than 2/5 of his head above her pelvic brim, you can do a symphysiotomy if CPD is mild, but section would be wiser. Remember that the head moulds less in a face presentation. If CPD is more than mild, section her.

CAUTION ! (1) Remember the possibility of anencephaly. Anencephalic babies often present by the face, but usually deliver easily. You should be able to distinguish anencephaly, a face, and a breech vaginally, once her cervix is 8 cm dilated; feel for his brow and his mouth. Occasionally, a lateral X-ray is useful. (2) If you are going to use oxytocin, use it with the greatest caution. (3) Never use a vacuum extractor!