(The full version of this wonderfully informative article by Linda F. Palmer can be found at: http://www.attachmentparenting.org/support/articles/artchemistry.php)
The Chemistry of Attachment (part 3)
Prolactin & Behavior
Prolactin is released in all healthy people during sleep, helping to maintain
reproductive organs and immune function. In the mother, prolactin is released in
response to suckling, promoting milk production as well as maternal behaviors.
Prolactin relaxes mother, and in the early months, creates a bit of fatigue
during a nursing session so she has no strong desire to hop up and do other
things.
Prolactin promotes caregiving behaviors and, over time, directs brain
reorganization to favor these behaviors 6. Father's prolactin levels
begin to elevate during mother's pregnancy, but most of the rise in the male
occurs after many days of cohabitation with the infant.
As a result of hormonally orchestrated brain reorganization during
parenthood, prolactin release patterns are altered. It has been shown that
fathers release prolactin in response to intruder threats, whereas childless
males do not. On the other hand, nursing mothers do not release prolactin in
response to loud noise, whereas childless females do. In children and
non-parents, prolactin surges are related to stress levels, so it is generally
considered a stress hormone. In parents, it serves as a parenting hormone.
Elevated prolactin levels in both the nursing mother and the involved father
cause some reduction in their testosterone levels, which in turn reduces their
libidos (but not their sexual functioning). Their fertility can be reduced for a
time as well. This reduction in sexual activity and fertility is entirely by
design for the benefit of the infant, allowing for ample parental attention and
energy. When the father is intimately involved with the infant along with the
mother, there should be some accord between the desires of the two, and oxytocin
and other chemicals provide for heightened bonding and non-sexual interest in
each other, which serves to retain a second devoted caretaker for the infant.
