Leukocyte and plasma zinc in maternal and cord blood: Their relationship to period of gestation and birth weight

Zinc is essential for growth. However, its therapeutic use in pregnant women to improve birth weight is not well established. Zinc status of mothers and newborns was determined using paired cord blood and maternal blood samples. Of the newborns investigated, 33 were full term with appropriate weight for date (AFD) (≥2.5 kg) and 30 were either full term (FT) small for date (SFD) (<2.5 kg) or preterm (PT) (<37 weeks gestation) babies. The cord plasma zinc was significantly higher compared with their corresponding maternal levels. However, cord leukocyte zinc was significantly (P<0.01) higher only in PT newborns. Maternal or cord zinc status had no association with birth weight. Plasma copper showed an inverse correlation to plasma zinc. These observations indicate satisfactory zinc status of pregnant women and newborns thus questioning the validity of extra zinc supplements to promote fetal and postnatal growth.