A team of UCLA-led researchers has found a link between early signs of adrenal puberty in first-born daughters and their mothers experiencing higher levels of prenatal stress. They did not find the same results in boys or girls who had not been born before.

The results of the 15-year longitudinal study were published in the February issue of Psychoneuroendocrinology.

The study was the first to identify early patterns of adrenal puberty as a result of prenatal stress. Adrenal puberty is marked by changes such as body hair growth, pimples and aspects of cognitive maturation, but does not include breast development or the onset of menstruation for girls or testicular enlargement for boys.

The discovery adds to research in the field of fetal programming, studies that explore the effects that stress and other factors affecting pregnant mothers can have on fetuses and babies after birth.

“This is a first-of-its-kind discovery and it’s fascinating to look at it through an evolutionary lens,” said UCLA anthropologist Molly Fox, who led the UC Irvine, UC Merced , led the study with colleagues from Chapman University and the University of Denver. .

Fox explains that the maturity of a first-born daughter, but not the early onset of menstruation, may enable her to help her mother successfully raise her other children. The daughter becomes mature enough to help care for the children while not yet capable of having children of her own, who will require her attention.

The finding also provides insight into the so-called “eldest daughter syndrome,” a sociocultural phenomenon discussed online that refers to child care and other domestic labor that first-born women often do, consciously or not. Consciously, conventionally takes to help. Parental or adult responsibilities are required to run the household. Online conversations tend to focus on eldest daughters who feel a strong sense of responsibility for their family’s well-being.

Researchers recruited participants for the study during routine first-trimester prenatal care visits at two obstetric clinics in Southern California. The women were on average 30 years old, all 18 years or older, and experiencing singleton pregnancies. For about half of them, it was their first pregnancy. All were English speakers, 45% were white/non-Latino and 30% were Latino. All were non-smokers and did not use steroid drugs, tobacco, alcohol or other recreational drugs during pregnancy. Of the children born to these mothers, 48% were female and 52% were male.

Women’s levels of stress, depression, and anxiety were measured at 15-, 19-, 25-, 31-, and 37-weeks gestation to create a composite score of prenatal psychological distress. They were also assessed two to three months after delivery to assign a composite postpartum distress score. The depression assessment asked respondents to rate the truth of statements such as “I felt lonely.” An example of an anxiety question was how often they felt certain symptoms, such as “irritability.”

At ages 8–10, 11–12, and 13–16 years, the children’s biomarkers of adrenal and gonadal puberty were measured separately, including body hair, skin changes, height gain or growth, and breast development. and the onset of menstruation (in women) are included. Voice changes and facial hair growth (in men). Hormone levels that are indicators of adrenal and gonadal puberty were measured by saliva samples at all diagnostic stages.

The study also measured childhood adversity by accounting for other factors that are associated with early puberty or puberty symptoms in children and adolescents. These include parental death or parental separation before age 5, father absence and low income-to-needs ratio at age 7-9.

“This research adds to the body of knowledge in our field that shows significant and lifelong effects on women and their offspring when it comes to prenatal emotional, environmental and other factors,” Fox said. said “This is important as we continue to seek practical and policy solutions that contribute to greater access to health care and the general well-being of expectant mothers.”