What people believe
By week 39 or 40, many pregnant women are uncomfortable and eager for labour to begin. The internet is full of lists of "natural induction methods" — and spicy food reliably appears alongside sex, walking, and nipple stimulation.
What the evidence says
There is no clinical evidence that eating spicy food initiates labour. No randomised controlled trial has shown a causal link between dietary capsaicin and the onset of uterine contractions or cervical ripening.1 ACOG does not list spicy food among methods of labour induction or cervical ripening.2
What spicy food can do during late pregnancy is aggravate heartburn and gastrointestinal discomfort — both of which are already common in the third trimester.
What to do instead
If you are at or beyond your due date and hoping for labour to begin, discuss evidence-based options with your provider. Membrane sweeping has some evidence supporting it. Medical induction with prostaglandins or oxytocin is the only reliably effective method. Eat what makes you comfortable, including spicy food if you enjoy it — but do not expect it to start contractions.