Association Between Mother-Infant Hair Cortisol Levels, Perinatal Stressors, and Adverse Birth Outcomes Among Kenyan Mother-Infant Pairs

Background: Few data on maternal-infant hair cortisol are available from HIV high-burden settings. We evaluated maternal hair cortisol and its relationship with infant hair cortisol, perinatal stressors, and pregnancy outcomes in Kenya. Materials and Methods: We analyzed data from an HIV prevention trial (NCT03070600). Pregnant women without HIV were enrolled and followed through 9 months postpartum. We utilized hair samples collected at 6 weeks postpartum from mother-infant pairs to quantify hair cortisol concentrations (HCC) reflecting cortisol levels over the prior similar to 3 months. HCC was measured by enzyme immunoassay. We tested whether mean maternal HCC was associated with infant HCC, stressors, and/or birth outcomes using linear regression. Results: Overall, 153 women had HCC available at 6 weeks postpartum. Median maternal age was 25 years (Interquartile range [IQR] 22-30), median completed education was 12 years (IQR: 8-12), and 95% were married. Median birthweight was 3.4 kilograms (IQR: 3.1-3.7), 13% of women experienced preterm birth (PTB), and 2% of infants had low birthweight (LBW); 11% were small-for-gestational age (SGA). Median maternal HCC was 12.0 pg/mg (IQR: 6.3-20.4); and median infant HCC was 10.4 pg/mg (IQR: 5.5-23.7). Infant HCC was correlated with maternal HCC (r = 0.498, p < 0.001). Stressors associated with maternal HCC (p < 0.05) included having a partner living with HIV or of unknown HIV status, relationship instability, and having high behavioral risk for HIV. Maternal HCC was not significantly associated with PTB, LBW, or SGA. Conclusion: In conclusion, peripartum maternal HCC was correlated with infant HCC and associated with experiencing HIV acquisition-related stressors.