Early disconnect with mom may speed onset of puberty in girls


A girl’s march toward early puberty may begin in the arms of her first caregiver, a new study suggests.

Against the backdrop of growing evidence that American girls are beginning pubertal changes at an ever-earlier age, a controversial researcher has found evidence that babies who fail to make a powerful early connection to their first caregiver are more likely to enter puberty early.

In a study published this week in Psychological Science, an international team of psychologists set out to explore how circumstances of early childhood, in combination with evolutionary pressures, may help explain findings that many girls in the United States are beginning the process of sexual maturation as young as 7 years old. They surmised that when parent-and-child bonds are not firmly forged in infancy -- a phenomenon called “insecure attachment” -- evolutionary pressures could push a girl to mature early, readying her for an earlier departure from the nest.

Both early puberty and poor infant attachment raise concerns. Girls who reach puberty earlier are at higher risk of certain cancers, including breast cancer, and are likely to engage in sexual activity earlier, bringing a higher risk of sexually transmitted disease and early pregnancy. Poorer attachment to a caregiver in infancy is thought to predict a higher risk of anxiety, depression and other psychological problems later in life.

The researchers note that other factors are implicated in the trend of earlier onset of puberty in girls, including better nutrition, higher rates of obesity and possible environmental exposures. They suggest that infant bonding may be one -- heretofore unrecognized -- influence among many.

The study also breaks down barriers between two very different realms of psychology--attachment theory and evolutionary psychology.

Psychologist Jay Belsky of Birbeck University London, along with researchers from Duke University and the University of Reading in the United Kingdom, tapped into a national trove of health and behavioral data collected on a large group of American-born babies from birth on. At 15 months, the researchers assessed the relationship between 373 baby girls participating in the federally-funded “Study of Early Child Care and Youth Development” and their mothers. Separating the babies from their mothers, and then reuniting them, allowed the researchers to gauge whether the babies were “securely attached” or emotionally distant from their mothers. (A securely attached baby typically greeted her mother’s return by smiling, vocalizing and reaching toward her parent; babies who looked away, fail to acknowledge or both advanced to and retreated from their mother upon her return were rated “insecurely attached.”)

Regardless of when their mothers entered puberty -- a powerful inherited influence on a female’s sexual maturation -- the researchers found that the more insecurely attached to her mother a baby girl was at 15 months, the earlier she would begin pubertal changes and the earlier she would mature sexually. Compared with baby girls who were deemed “securely attached” to their moms, those who demonstrated indifference or avoidance upon their mother’s return were almost 2 1/2 times more likely to begin pubertal changes by 10 1/2 years old and to have pubic hair and breast development and to have begun menstruating by 13 1/2.

Belsky has spurred controversy with studies suggesting that long hours of childcare for infants and young children outside the home may weaken a child’s attachment to his or her primary caregiver -- usually Mom -- and negatively affect the child’s later behavior at school. The importance of an infant’s attachment to Mom is not widely debated. But debates have long raged over what factors -- a child’s temperament, the mother’s employment outside the home, a depressed parent -- may contribute to the security of that bond.

“This apparent accelerating of attachment insecurity that we discerned ... necessitates a rethinking of the functional significance of the secure and insecure attachments that figure so prominently in the study of human development,” the authors wrote.

In other words, according to the researchers, forging a powerful emotional bond with your baby girl may help to assure more than her emotional health. It might influence her physical health as well.

-- Melissa Healy / Los Angeles Times