Fetal and maternal factors associated with infant mortality in vervet monkeys

Background Causes of infant death remain unknown in significant proportions of human and non-human primate pregnancies.Methods A closed breeding colony with high rates of infant mortality had pregnancies assessed (n = 153) by fetal measurements and maternal characteristics. Infant outcome was classified as neonatal death (stillborn or died <48 hours from birth), postnatal death (died 2-30 days) or surviving (alive after 30 days).Results Fetal size did not predict outcome. Poor maternal glycemic control and low social ranking increased odds for adverse outcome (OR = 3.72, P = 0.01 and 2.27, P = 0.04, respectively). Male sex was over-represented in stillbirths (P = 0.04), and many were macrosomic, but size did not associate with maternal glycemic control measured as glycated hemoglobin A1c. Postnatally dead infants were smaller (P < 0.01), which associated with behavioral factors and glycemic control.Conclusions Fetal growth estimates predicted gestational age but not fetal outcome. Maternal social status and metabolic health, particularly glycemic control, increased risks of adverse pregnancy outcome.