Diet-induced Zn deficiency in pregnant rats is known to cause cong. malfs. in 90-100% of their progeny, some 3% having spina bifida(SB).Mothers of children with SB have been reported to have high concentrations of hair Zn. Recent UK claims suggest vitamin A/folic acid periconceptional supplementation dramatically reduces the rate of recurrence of NTDs in women at risk.Because animal data have established a consistent relation between low plasma vitamin A and Zn deficiency, we studied the Zn status of women with a NTD fetus.Toenail clippings obtained mostly between 18-24 wks gestation provides a valuable retrospective assessment of maternal Zn status in the months prior to & around the periconceptional period.Zn analyses of toenails were performed by neutron activation analysis on 35 patients.21 controls (7 matched normal pregnancies, 14 normal females & males) had a normal range for Zn of 79.6-125 ppm.10 mothers with NTD fetuses, 2 with omphalocele, & 2 with with exogenous Zn intake were analyzed. High Zn values were found in 2 with SB fetuses (181;144), 1 with anencephaly (Anen.)(213), & 2 with Zn intake (208.4;290.8).Lowest value of all 35 was 1 with anen.(62.3).2 with SB+other malfs., 2 with Anen, 1 with lone SB all had normal Zn.In Zn deficiency both decreased and paradoxical increased Zn values have been found in hair.The consonance of our findings of high (3) or low(1) toenail Zn values among 10 mothers with NTD fetuses, suggests an abnormality in Zn metabolism in some women who bear children with NTDs.