New mothers who are mildly deficient in iron may have trouble properly bonding with their baby, US research suggests.
Early bonding is thought to be important
A study by Penn State University of 95 South African women found those with anaemia were less emotionally in tune with their babies.
Loss of blood during childbirth can often lead to anaemia - particularly among women who do not take vitamin supplements during pregnancy.
The study was presented in San Diego at an Experimental Biology conference.
Previous studies have shown that anaemic women may be more prone to depression in the period immediately after giving birth.
They also experience a slow down in thinking and memory.
Researcher Dr Laura Murray-Kolb said: "Our new results suggest that the effects of mild iron deficiency can disrupt the solid foundation that is established by healthy mother/infant interactions."
The researchers compared 64 South African mothers who were mildly iron deficient with 31 who were not.
At 10 weeks after childbirth, the women and their babies were videotaped interacting.
Half of the iron-deficient women were then given iron supplements.
After nine months, all of the women were videotaped interacting with their babies again.
Analysis of the tapes showed women who were iron sufficient and those who received supplements seemed to be more emotionally available to their babies.
The mildly iron-deficient mothers were less sensitive to their baby's sounds.
They also scored lower on giving their babies chances to lead interactions.
In addition, the iron-deficient mothers cut in on the baby's play at inappropriate times more often and appeared bored or distant more frequently than the other mothers.
At nine months, the babies of the three groups of mothers also behaved differently.
The babies of the mildly iron-deficient women were less responsive and less involved with their mothers.
And when moving away, the babies would depend less on their mother for reassurance.
Dr Murray-Kolb said: "New mothers should be aware of their iron status which, we know now, affects the child as well as the mother.
"Iron deficiency is easy to correct and could be a big part of post-partum problems with mother/child interactions."