What is the biological role of positive feedback loops? describe an example:

Example: a baby breastfeeding from its mother: when the baby feeds, more prolactin is released (hormone that stimulates milk production), which in turn produces even more milk. When the baby stops breastfeeding, there will be no more positive feedback and the breast tissue will no longer produce milk any more.

another example: childbirth: when the baby is coming out, the muscles contract. This releases a hormone to contract the muscles even more! So that the baby can come out. 

This is giving me a headache i have asked others and they don’t know it either