1Laboratory of Comparative Ethology, Eunice Kennedy Shriver National Institute of Child Health & Human Development, NIH, 2Department of Psycology, University of Massachusetts Amherst
March 26, 2015 , Archview Ballroom
Rhesus monkeys frequently show significant hair loss late in the peripartum period and regain full coats when their infants are a few months old. While pregnancy is a known risk factor for the occurrence of alopecia, the relationship between hair loss, chronic hormone circulation, and maternal investment is not understood. We tested the hypothesis that hair loss in pregnant females is associated with greater infant investment in 41 female rhesus monkeys (Macaca mulatta) throughout the 2013 birthing season at the Laboratory of Comparative Ethology at the NIH Animal Center in Poolesville, MD.
We analyzed 1) photographs for alopecia severity and hair samples for chronic cortisol in April (pregnancy), July (early lactation), and October (late lactation), as well as 2) fetal measurements via ultrasound in pregnancy and 3) milk yield volume (MYV) and infant growth rate (g/day) in the neonatal period (first 30 days). We found that the severity of hair loss in early lactation was predicted by higher HCCs in pregnancy (R2=0.16, p=0.01). Moreover, mothers with hair loss has smaller fetuses than those with normal coats (p<0.01), but showed significant positive correlations between HCCs in pregnancy and both MYV (r=0.84, p<0.01) and infant growth rate (r=0.66, p<0.05) in the neonatal period whereas mothers with normal coats showed no such relationship. These findings suggest that 1) maternal cortisol may program milk production and therefore infant development, and 2) that mothers who are already constrained may be saving their resources for the early neonatal period rather than the prenatal period.
This research was supported by funds from the NICHD Division of Intramural Research and by NIH grant R24OD01180‐15 to MAN.