Oxytocin
Oxytocin is produced in the hypothalamus and released into the blood by the posterior pituitary.
In pregnancy and childbirth, it plays an important role in starting and regulating contractions and the delivery of the placenta. It also affects let down of breastmilk and release through the nipples.
Oxytocin acts in the brain and affects behaviour, such as sexual arousal, feelings of trust, attachment, and bonding.
Research is being carried out to investigate the role of oxytocin in depression, anxiety and post-traumatic stress.
You may have heard oxytocin referred to as the “cuddle hormone”.
Further reading at You & Your Hormones here.
Oxytocin deficiency or excess
Not enough is yet known about this and more research is needed.