https://www.selleckchem.com/products/gdc-0068.html Cluster 2 showed scores below the mean in both math scores, whereas cluster 3 exhibited performances above the mean in both math scores. No math differences were found between cluster 1 and 3. The data yield evidence that the association between CEF and math achievement depends on the specific math skill and test type. The results underline the importance of differentiating between CEF components and specific math abilities. Implications for future research on the associations between mathematics, ADHD and CEF are discussed.Background Maternal stress during pregnancy can influence the trajectory of fetal development, shaping offspring physiology and health in enduring ways. Some research implicates fetal programming of the hypothalamic-pituitary-adrenocortical (HPA) axis as a mediator of these effects. The present study is the first to examine child hair cortisol concentration (HCC) and maternal stress during pregnancy in a diverse, low-income sample. Methods The sample consisted of 77 healthy, low-income (M annual income $13,321), mother-children pairs (M child age = 3.81 years, SD = 0.43). The children were 57 % girls, 43 % boys. Mothers were 65 % Latina/Hispanic, 28 % Non-Hispanic White, 7% Black/African American. Maternal prenatal stress was measured with the Perceived Stress Scale administered by interview in the second and third trimesters, and again approximately four years later when child hair samples for assaying HCC were collected. Results On average maternal perceived stress increased significantly across pregnancy, then returned to lower levels 4 years after birth. Regression analysis revealed that child HCC was not significantly predicted by maternal perceived stress at either single prenatal time point. Exploratory analysis revealed evidence of a relation between increases in maternal prenatal stress from second to third trimester and child HCC four years later (r = .37, p = .04). Conclusions These re