The phrase "active labor" refers to the stage of childbirth where the contractions become stronger, longer, and closer together, leading to the baby's birth. Full definition
Three hours later I was in active labor in my bathroom, under the shower. (birthwithoutfearblog.com)
Soft music decreased both sensation and distress of active labor pain in the first three hours and delayed increases in the distress of pain for an hour. (sheknows.com)