 Even women who show little reaction to labour pains, in comparison to other women, show a substantially severe reaction to crowning (the appearance of the baby's head).Back labour is a term for specific pain occurring in the lower back, just above the tailbone, during childbirth.During the later stages of gestation there is an increase in abundance of oxytocin, a hormone that is known to evoke feelings of contentment, reductions in anxiety, and feelings of calmness and security around the mate.