In 1986, researchers Marshall Klaus, John Kennell, Steven Robertson, and Roberto Sosa in the United States published “Effects of Social Support During Parturition on Maternal and Infant Morbidity,” hereafter “Effects of Social Support...” in the British Medical Journal.

Marshall Henry Klaus was a scientist and pediatrician who studied maternal-infant bonding in the twentieth century in the United States. Maternal-infant bonding is the psychological and chemical attachment between mother and infant. Klaus cofounded DONA International, an organization that trains birthing aides, called doulas, to provide physical and emotional support to laboring mothers.