When it comes to parenting, teenage mothers fuss more over their baby's fashion and are less likely to ooh and ah with their infants than women who give birth later in life.

Preliminary findings published in the January issue of Hormones and Behavior indicate that adult mothers are more affectionate with their babies, while teen moms tend to focus on "instrumental" behavior, such as changing a diaper or straightening a bib.

The result surprised study researchers, who had theorized that teen moms would display more inappropriate behavior such as poking and prodding. Previous medical research has indicated such conduct.

For the study, 119 new mothers were broken down into three age groups: teens (aged 15 to 18), young mothers (aged 19 to 25), and mature mothers (aged 26 to 40). Each woman was videotaped interacting with her baby at home for 20 minutes, and was asked about her childhood experiences and present mood.

Researcher Katherine Krpan of the University of Toronto at Mississauga, found that mothers who received constant care and affection as a child were warmer toward their babies than those who had multiple caregivers.

Krpan and colleagues also questioned whether the hormone cortisol (search) played a role in the maternal responses. Cortisol is usually associated with stress, but research shows that, in healthy young mothers, the hormone may result in better mood and greater attention during the postpartum period.

Three saliva samples were obtained from each mom during the course of the study. Teen mothers who were breastfeeding had higher salivary cortisol levels than mature mothers, resulting in increased energy and fewer negative moods.

"In mature mothers, average cortisol levels were lower, but cortisol related to decreased energy and negative affect," the authors wrote in the journal report.

"As age increased, the relation between higher cortisol levels and mood and fatigue changed from positive to negative," they continue.

Researchers say it's unclear whether cortisol levels, age, or their interaction is the most important driving force behind maternal behaviors. More research is needed.

By Kelli Miller Stacy, reviewed by Brunilda Nazario, MD

SOURCES: News Release, University of Toronto, Krpan, K. "Experiential and hormonal correlates of maternal behavior in teen and adult mothers," Hormones and Behavior, January 2005; vol 47: pp 112-122.