Final answer:
The least effective technique for a woman with a persistent occiput posterior position is lying supine and relaxing. Positions such as sitting or kneeling and leaning forward, rocking the pelvis, and squatting are generally more beneficial for encouraging fetal rotation and relieving back strain. Carpenter's trick of gripping a nail with pliers prevents bending by reducing the wobbling length.
Step-by-step explanation:
The least effective technique for a woman with a persistent occiput posterior position is a. Lie supine and relax. This position does not favor the rotation of the fetus and might not alleviate the back pain associated with this fetal position. On the other hand, b. Sitting or kneeling, leaning forward with support, c. Rocking the pelvis back and forth while on hands and knees, and d. Squatting are all positions that can help encourage the baby to turn to an anterior position and can also help relieve back strain due to the weight of the baby.
Pregnant women often suffer from back strain late in the pregnancy due to the increased weight of the baby, which shifts the center of gravity forward, causing a change in posture and additional stress on the back muscles. The old carpenter's trick of gripping the nail with pliers works because holding the nail this way reduces the effective length that can wobble and bend, providing stability when the nail is being hit.