Study shows connection between prenatal stress and early maturation of oldest daughters

FRESNO, Calif. (KFSN) -- Have you ever heard the term - Eldest Daughter Syndrome?

It's not an official psychiatric diagnosis, but according to doctors, it describes the challenges and expectations that are often placed on the oldest daughter in a family.

The trending term now looks to be backed by the scientific research of a UC Merced professor.

Growing up, Fresno resident Carol Riley was the oldest of her five siblings. At the age of six, she remembers taking on some of her mom's responsibilities when it came to her siblings.

"I think because I could see that there was more help needed around the house, and so I don't remember her asking me to do it. I think it just came naturally," Riley said.

Her mother, Evelyn Bennett, shared that Riley would help with diapers.

"She seemed to catch on to what things were and other things at an early age, and so if I needed something someplace else, I would ask 'Would you get that for me?' She would, and it seemed like she just grew up," Bennett said.

As the oldest, Riley also built a strong sense of leadership.

"Being the oldest, I was very bossy," Riley said.

Bennett recalls getting surgery and having to recover at home.

"I could have very well told the kids what to do, but she was doing it," she explained. "I almost said something: 'Carol, you can stand down now.'"

Riley always felt she matured faster compared to other girls her age at the time.

A new study shows the reason behind early maturation.

"Research has shown that girls are much more sensitive to stress in the lifespan, in terms of the timing of their puberty," explained Jennifer Hahn-Holbrook. "The timing of puberty is really important because it affects the ability to do childcare, it affects the ability to have that socio-emotional kind of awareness of one sibling."

Hahn-Holbrook is an assistant professor of psychology at UC Merced. She was part of a UCLA-led research group -- which found a connection between early puberty and prenatal stress.

Bennett shared with Action News that she was in the hospital with a kidney infection when she was six months pregnant with Riley.

"She must have been so worried about the health of herself and her baby," Hahn-Holbrook said. "So that's a classic example of stress and pregnancy."

Learning about the study, Riley now feels her experience of being the eldest daughter has been validated.

"I never resented being the oldest, but I did get tired of being the oldest," she said.

It also gave Bennett the chance to express her gratitude.

"I've always appreciated how much you helped me through the years," she said.

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