The study, conducted by University of Michigan sociologist Jennifer Barber and University of California, San Diego, sociologist Patricia East, analyzed data from a national sample of more than 3,000 mothers and their 6,000 children representing a broad socioeconomic spectrum. The families were studied over a period of eight years, from 1986 through 2004. The study is published in the May issue of Child Development.

Funding for the analysis was provided by the National Institute for Child Health and Development.

"Our study underscores the important role of children's birth intention status in distributing parenting resources to children within a family," said Barber, a research professor at the U-M Institute for Social Research (ISR) and an associate professor in the U-M Department of Sociology.

For the study, women who had recently given birth were asked, "Just before you became pregnant, did you want to become pregnant when you did?" If they answered yes, the birth was classified as intended. If they answered no, they were then asked if they wanted another baby, just not at that time, or whether they didn't want a baby at all. The researchers found that 24 percent of pregnancies were mistimed, and 10 percent were unwanted.

The researchers examined two types of resources parents provide to their children: home learning materials and opportunities, and maternal warmth and responsiveness. They used mothers' reports and interviewer observations to assess how many children's books were in the home, for example, and how often parents read to the child and taught the child new skills, including counting and learning the alphabet.

They assessed the mother's parenting style, the time the family spent together, the time the father spent with the child, and the extent to which parents promoted the child's independence. They also observed the mothers' direct interactions with the children, including conversations and spanking or slapping.

The researchers found a statistically significant and consistent relationship between the intention status of a child's birth and these scores. Across the income range, children whose births were unintended had access to fewer family resources and less maternal warmth. And the resources provided to older children decreased more after the birth of an unintended child than it did after the birth of a child that was intended.

"Inequitable parental treatment is known to have significant long-term negative effects on the adjustment and self-esteem of the slighted child," Barber and East wrote. "It is certainly plausible that parents' tendency to treat unwanted children more harshly in general, as well as their tendency to be more harsh in parenting unwanted children in comparison to wanted children, contribute to the poor outcomes of unwanted children." These outcomes include disproportionately high rates of school failure, behavior problems and low self-esteem.

Barber is currently conducting another study on unintended pregnancy using a new, prospective measure that she hopes will elucidate the complex feelings young women often have about getting pregnant, and illuminate why rates of unintended pregnancies and births remain relatively high.

Provided by University of Michigan