Potential Scientific Basis for Eldest Daughter Syndrome Revealed
In a groundbreaking study published in the February issue of Psychoneuroendocrinology, researchers have found a correlation between early signs of adrenal puberty in first-born daughters and their mothers experiencing high levels of prenatal stress.
The University of California, Los Angeles-led research team, which includes anthropologist Molly Fox, has been delving into the field of fetal programming, a study that explores how stress and other emotional and environmental factors women experience during pregnancy affect their children long after birth.
The study accounted for other factors known to correlate with early maturation or signs of puberty in children, such as childhood adversity, the death of a parent, divorce before age 5, the absence of a father, and economic uncertainties at ages 7-9. Even after accounting for these factors, the study found that eldest girls matured the fastest when their mothers experienced high levels of prenatal stress.
The study involved recruiting women from two obstetric clinics in Southern California during routine first trimester prenatal care visits. The participants were nonsmoking, not using steroid medications, tobacco, alcohol, or other recreational drugs during pregnancy, and all were over 18 years of age.
Of the children born to these mothers, 48% were female and 52% were male. The study measured characteristics of both adrenal and gonadal puberty in the children, including body hair, skin changes, growth in height or growth spurts, breast development, and the onset of menstruation in females, and voice changes and facial hair growth in males.
The findings are fascinating, according to Fox, who explains that fetal programming involves the fetus getting cues about what the world is going to be like, and the body can flexibly adjust the shape of the life-cycle to be optimally suited to those conditions expected.
Adrenal puberty does not include breast development or the onset of menstruation for girls. Instead, it fosters social and cognitive changes, including emotional maturity. This could potentially explain why eldest daughters are more likely to hold leadership roles, as suggested by a 2012 study.
The study's authors are thrilled that their work is now available for the public to read, especially after following the families along for so long. The internet is already buzzing with discussions about the study, with numerous thinkpieces and tweets about the plight of oldest daughters.
This study adds to the growing understanding of the complex interplay between maternal stress during pregnancy and the long-term effects on children. As research continues, we may gain a deeper understanding of how we can support mothers during pregnancy and help ensure the best possible start for their children.
