(brak´stәn hiks´) light, usually painless, irregular uterine contractions that occur throughout pregnancy, gradually increasing in intensity and frequency and becoming more rhythmic during the third trimester; they are often mistaken for true labor and are sometimes referred to as “false labor.” They may be stimulated by the descent of the head of the fetus into the pelvic inlet. are not as regular and rhythmic as the uterine contractions of true labor .