Last reviewed 01/2018
Pain fibres from the body of the uterus pass with sympathetic nerves through the hypogastric plexus and the lumbar splanchnic nerves to the dorsal roots of the lowest thoracic and upper sacral vertebrae. This is the pathway which transmits the pain of uterine contractions during the first stage of labour.
Pain signals from cervical dilatation pass in the pelvic splanchnic nerves to the dorsal roots of the upper sacral nerves.
Pain is also felt in the lower vagina, vulva and perineum. Pain fibres pass via the pudendal nerve to the dorsal horns of S2, 3 and 4.