Deficient maternal zinc intake—but not folate—is associated with lower fetal heart rate variability

•We evaluate maternal intake of zinc and folate on fetal autonomic system development.•A dietary form and fetal heart rate were collected from 3rd trimester pregnant adolescents.•Deficient zinc, but not folate, was associated with less fetal heart rate variability.

ObjectiveFew studies of maternal prenatal diet and child development examine micronutrient status in relation to fetal assessment.MethodsTwenty-four-hour dietary recall of zinc and folate and 20 min of fetal heart rate were collected from 3rd trimester pregnant adolescents.ResultsDeficient zinc was associated with less fetal heart rate variability. Deficient folate had no associations with HRV. Neither deficient zinc nor deficient folate was related to fetal heart rate.ConclusionsThese findings, from naturalistic observation, are consistent with emerging data on prenatal zinc supplementation using a randomized control design.Practical ImplicationTaken together, the findings suggest that maternal prenatal zinc intake is an important and novel factor for understanding child ANS development.