hormone

An increase in oxytocin leads to an increase in contractions until the baby is born. It is positive feedback because the presence of oxytocin promotes more oxytocin production. If it were negative feedback, the presence of oxytocin would inhibit the production of oxytocin to maintain set-point levels in homeostasis.

Childbirth is one of the few examples of positive feedback systems in the body.

In the diagram below, parturition means the process of bringing forth a baby.

Note that this also occurs during the suckling process of during nursing. The more the baby sucks, the more milk that is produced.