Brow presentation does not mean caesarean section

Dear Sir,

We managed to deliver two cases of brow presentation vaginally using the ventouse. The first patient was a primipara at term, who presented with a brow presentation in the pelvic cavity in a frontoanterior position. She had been pushing for 1 h before the diagnosis was made. She already had effective epidural analgesia. A posterior metal cup was inserted near to the posterior fontanel and this was used to flex the fetal head by pulling during uterine contractions and maternal pushing. After head flexion and descent with the ventouse over three contractions, a low forceps achieved delivery in a face to pubis position with a large episiotomy. The baby weighed 4,010 g and was in good condition and Apgar scores were 8 and 10 at 1 and 5 min, respectively. The head showed the typical moulding of an impacted brow presentation. There was no significant fetal or maternal trauma.

The second case was a patient with three previous vaginal deliveries. Labour was induced at 42 weeks. Brow presentation was diagnosed at full dilation in a mentoanterior position. The lowest point of the head was at the spines. No head flexion was noted during contractions. The pelvis was capacious. The patient was using entonox for analgesia.

A Kiwi ventouse cup was inserted behind the head to the flexion point near the posterior fontanelle. During the first contraction with maternal pushing, the ventouse achieved head flexion in a left occipitoposterior presentation. With further pulls and maternal pushing during the following two uterine contractions, the head delivered face to pubis. A small first-degree perineal tear was repaired under local anaesthesia. The baby weighed 4,195 g and was in good condition with no trauma. Apgar scores were 9 and 10 at 1 and 5 min, respectively.

Discussion

Traditionally, the management of brow presentation has been the delivery by caesarean section. The fetal head in brow presentation approaches the pelvis by the mentocervical diameter of 13.5 cm, which is larger than the diameters of the pelvic brim. This precludes head engagement. However, Arthure (1957) reported a case with X-rays showing the head had actually engaged as a brow and then underwent spontaneous rectification to a vertex presentation within the pelvic cavity.

Spontaneous flexion of the fetal head to vertex or deflexion to face presentation may occur as a result of uterine contractions. Manual conversion of brow presentation has been used to correct the deflexion of the fetal head (Abell 1973). Some authors recommended manual conversion once the cervix is fully dilated. Chapman (2000) reported a series of six cases of brow presenting within the pelvic cavity in frontoanterior position during the second stage of labour. All six women were delivered by Kielland's forceps rotation and extraction.

Luker (2005) used a Kiwi ventouse cup to flex a brow presentation to occipitoposterior in two cases. Pulling to flex the head was applied between uterine contractions. In one of these cases, gradual head flexion was achieved by multiple consecutive applications of the cup along the fetal head toward the occiput.

In our two cases, however, head flexion was achieved by pulling during contractions with maternal pushing. The recommended criteria we suggest to be present before undertaking such a delivery are: brow presentation should be engaged in the pelvis and in a frontoanterior position. The pelvis should be capacious to allow the ventouse cup to be inserted posteriorly and to reach the occiput. Furthermore, it is essential to apply the cup primarily on the flexion point near the posterior fontanel.

The Kiwi cup is more appropriate than the posterior metal cup for this use as it is smaller and thinner. Moreover, the metal cup has a projection on the centre of its back to attach the pulling chain, which occupies more space making the insertion more difficult and cause more friction against maternal tissue that may lead to vaginal lacerations.

The RCOG Guidelines (2005) on operative vaginal delivery mentioned the use of ventouse as the first choice instrument as it causes less pelvic floor injuries than forceps. Moreover, rotational delivery with the Kielland forceps requires specific expertise and training. Engaged brow presentation at full cervical dilatation creates management difficulties. Achieving vaginal delivery in these situations would avoid the need for a difficult caesarean with a fully dilated cervix and impacted head.