does drinking pineapple juice induce labor
Juice and canned pineapple does not contain the enzyme called bromelain. The mechanism by which pineapple contributes to inducing labor is attributed to proteolytic action of bromelain. Bromelain might help to soften the connective tissue of the cervix and, thus, bring on labor.
While it's not exactly a food, pregnant women have ingested castor oil to induce labor for centuries. The oil is extracted from the bean of the castor plant. Research studying the efficacy of castor oil as a labor inducer is inconclusive; though some women swear it helped stimulate their contractions.