A just-published study is the very first to connect oyxtocin in humans to the bond between mother and child.
Numerous animal studies -- in mice, rats and prairie voles -- have shown a strong connection between oxytocin and maternal behavior, while Kerstin Uvnas-Moberg did a series of studies of human mothers showing a relationship between breastfeeding and a mother's feelings of calm and connectedness. But cautious scientists have been reluctant to say what feels so true -- that oxytocin bonds humans in all the ways it does animals.
This study from Bar-Ilan University led by Ruth Feldman found a strong correlation between oxytocin levels and mothers' feelings toward their babies during pregnancy and after birth. From the APS story posted on Scientific Blogging:
Initial levels of oxytocin at the first trimester predicted bonding behavior. Therefore, mothers with a high level of the hormone at the beginning of the pregnancy engaged in more of the aforementioned bonding behaviors after birth.
Additionally, mothers who had higher levels of oxytocin across the pregnancy and the postpartum month also reported more behaviors that support the formation of an exclusive relationship (i.e. singing a special song to the infant, or bathing and feeding them in a special way). These mothers were also more preoccupied by thoughts of checking on the infant, the infant’s safety when they are not around, and the infant’s future.
I reported on this study in my book, ahead of its publication the journal, and corresponded with one of th researchers, Ari Levine. He told me something a bit different -- that it wasn't a mother's oxytocin level, but how much her oxytocin level increased that predicted bonding.
In fact, that's what the study showed:
The increase in OT from early to late pregnancy correlated with higher maternal-fetal bonding.