Instead of the normal well-flexed attitude with the limbs and head flexed on the trunk and the rounded back pointing towards the mother’s soft abdominal wall, the fetal spine faces the forward curve of the maternal lumbar spine and good flexion is not possible. The fetal spine is straightened, the head is held in a deflexed position known as the ‘military position’ and the anterior fontanelle is found directly over the internal os. The term ‘bregmatic presentation’ is sometimes used (Lewis 2004). This position of the head brings larger diameters into relationship with the pelvic brim and engagement of the head may not occur.

Hunter et al (2007) discuss the benefits of upright and leaning-forward postures in order to encourage the fetal head to engage in the optimal occipitoanterior position. Avoidance of a reclining position with the knees higher than the hips will reduce the incidence of occipitoposterior position of the fetal head at the commencement of labour (Sutton 2001). Taking up an all-fours posture may reduce the pressure of the fetus on the maternal spine and help to reduce backache. It may also aid rotation of the fetus to an occipitoanterior position (Simkin & Ancheta 2005).

It has been suggested that in the antenatal period if a woman adopts a hands-and-knees posture leaning forward then this might promote a favourable position of the baby (Hunter et al 2007). Three trials (2794 women) were included in a systematic review (Hunter et al 2007) to explore this issue. Two trials were focused on the antenatal period. In one trial (100 women), four different postures (four groups of 20 women) were combined for comparison with the control group of 20 women. Findings were that in the lateral or posterior position the presenting part of the fetus was less likely to persist following 10 min in the hands-and-knees position compared to a sitting position. In a second trial (2547 women), advice to assume the hands-and-knees posture for 10 min twice daily in the last weeks of pregnancy had no effect on the baby’s position at delivery or on any of the other pregnancy outcomes.

Simkin & Ancheta (2005) detail the advantages of ambulation and forward-leaning positions in labour. Freedom to move around in the first stage of labour and the maintenance of an upright position such as can be achieved by sitting astride a chair and leaning on its back have been shown to be beneficial to women with an occipitoposterior presentation. Descent of the fetal head is encouraged and good uterine contractions should follow. Progress is more likely to be normal, culminating in long internal rotation of the occiput (see below). In the second stage of labour, the squatting position increases the anteroposterior diameter of the outlet and may aid rotation, descent and delivery.

The third trial in the systematic review of Hunter et al studied the use of hands-and-knees position in labour. The sample comprised 147 labouring women at 37 or more weeks’ gestation, where the fetal occipitoposterior position was confirmed by ultrasound. Randomisation occurred: 70 women (intervention group) assumed hands-and-knees positioning for a period of at least 30 min compared to 77 women (control group) who did not assume hands-and-knees positioning in labour. There was no statistical significance in the reduction of occipitoposterior or transverse positions at delivery and operative deliveries. However, there was a significant reduction in back pain. The authors conclude from the evidence in the systematic review (Hunter et al 2007) that adopting these positions as a recommended intervention could not be endorsed. However, they stated that if the women find these positions comfortable then they should adopt them and especially in labour where maternal backache is reduced.

To relieve the backache, many women find the kneeling position beneficial. This position may also aid rotation of the head to an occipitoanterior position. Massaging the woman’s back in the lumbosacral region may also help to relieve the backache and a warm bath has been found to be helpful. Epidural analgesia is the most effective method of relieving the pain. In the second stage of labour, perineal trauma is minimised by an upright position (Aasheim et al 2007).

A difficult problem for the woman in the late first stage of labour is feeling a strong urge to push before full cervical dilatation. Pushing presses the fetal head against the cervix and oedema may occur, thus lengthening the transitional stage of labour. Simkin & Ancheta (2005) suggest that the adoption of the kneeling position with the head resting on the forearms may lessen the pressure on the cervix.