Early in pregnancy it is useful to encourage the mother to do some gentle exercise to offset some of the mechanical strain that will arise with postural changes. Manipulation of the lumbar spine and pelvic joints is possible until the sixth month for primigravidae and the fourth or fifth month for multiparae. The joints and soft tissues will respond very readily to gentle stretching techniques because of hormonal changes. It is appropriate for midwives to have a good working knowledge of the mechanical advantages and disadvantages of different maternal positions adopted during labour.