Oxytocin

Oxytocin is a hormone that triggers contractions at the end of pregnancy and thus leads to birth. During the breastfeeding period, oxytocin also ensures that breast milk is shot in. Since it can convey very positive feelings, it is often called cuddly hormone. The distribution takes place via the posterior lobe of the pituitary gland directly into the bloodstream.

https://de.wikipedia.org/wiki/Oxytocin _{(Wikipedia CC-by-sa-3.0)}