A pregnant woman in labour who cannot urinate as a result of compression on the outflow tube (urethra) from the bladder, will have great discomfort. At the same time, the full bladder will further obstruct the passage of the unborn baby by occupying space in the pelvis. She needs to have a catheter (sterile rubber or plastic tube) inserted into her bladder to let the urine out before you refer her to a higher health facility. The technique is called catheterisation. This procedure may even allow the birth of the baby to progress. Without it, if labour begins, she may be unable to give birth normally. Women who are a long time in labour may also need catheterisation if their bladder becomes obstructed. If the woman's bladder is distended it will feel like a soft bag of water lying above her pubic bone. When she is lying flat on her back, you may see the full bladder as a rounded mass.
Tell her what you are going to do and why she needs the procedure. Then ask her to lie on her back with her head lifted and her legs flexed, with feet wide apart. Cover her lower body except the genital area with a clean cloth to reduce embarrassment for her if other people are present.