Occiput Transverse Position

Occiput transverse position is a fetal head that enters the pelvis with the occiput pointing to the maternal left or right, so that the sagittal suture lies in the transverse diameter. It is the usual position at engagement in many women, and most heads rotate to occiput anterior as they descend. It matters because failure to rotate causes slow descent, deep transverse arrest, assisted delivery and caesarean section.

• Risk factors: flat (platypelloid) or android pelvis, first labour, deflexed head, epidural, anterior placenta, large baby.
• It is a normal stage of labour when rotation follows.
• Persistence beyond the mid pelvis is abnormal.

Women have a normal early labour with slower progress in the second stage than expected, and early rupture of membranes in some. Examination shows the sagittal suture crossing the pelvis from side to side.

• Sagittal suture in the transverse diameter, with both fontanelles at the sides.
• Back felt at the side on abdominal palpation.
• Differential diagnosis: occiput posterior position, occiput anterior in early rotation, asynclitism, deep transverse arrest, face or brow presentation, cephalopelvic disproportion.
• Complications: slow descent, arrest of descent, deep transverse arrest, prolonged second stage, assisted delivery, caesarean section, perineal tears, postpartum haemorrhage.

The diagnosis is by vaginal examination with ultrasound when in doubt.

• Vaginal examination: sagittal suture running side to side, position of both fontanelles (anterior and posterior at opposite sides), ears, station, flexion and caput.
• Abdominal palpation: back at the maternal flank, head engagement.
• Transabdominal ultrasound for occiput position (midline echo transverse, orbits at the side).
• Cardiotocography; assessment of the pelvis; estimated fetal weight.

The principle is to allow time and favourable positions for rotation, support weak contractions and assist rotation only when the head fails to descend.

• Supportive: upright, kneeling, hands and knees and lateral positions; asymmetrical positions (lunge, one knee up); hydration (oral fluids or Ringer's lactate 1 litre IV over 1 to 2 hours); empty the bladder; one to one support; continuous cardiotocography on oxytocin; delayed pushing with epidural.
• Pharmacological: oxytocin 10 IU in 1 litre Ringer's lactate (10 mU/mL) started at 12 mL per hour (2 mU/minute) and doubled every 30 minutes to a maximum of 192 mL per hour (32 mU/minute) for weak contractions without disproportion; lignocaine 1 percent 10 mL each side for pudendal block or 10 to 20 mL (maximum 3 mg/kg, not above 200 mg) for perineal infiltration; amoxicillin-clavulanate 1.2 g IV as a single dose after operative vaginal delivery; cefazolin 2 g IV before caesarean section; oxytocin 10 IU IM after birth, then 20 IU in 1 litre at 125 mL per hour for 4 hours.
• Procedures: manual rotation to occiput anterior at full dilatation with flexion of the head; rotational forceps or vacuum by an experienced operator; caesarean section for failure of descent after rotation attempt, a high head, disproportion or fetal compromise.
• Special groups: epidural analgesia allows an extra hour for rotation; a uterine scar uses oxytocin only with senior review and continuous monitoring.
• Red flags: no descent after 1 hour of pushing, abnormal fetal heart rate, thick meconium, scar tenderness, fever above 38 degrees Celsius.
• Follow-up: bladder catheter for 24 hours after assisted birth; examine the perineum for sphincter injury; review at 6 weeks.