Zinc concentration in hair and serum of pregnant women in Belfast.

Serum and hair levels of zinc were estimated in 28 nonpregnant women and 60 pregnant women at 20 to 22 wk of gestation (2nd trimester), 36 to 37 wk of gestation (3rd trimester), and 3 days postpartum. The mean serum zinc concentration was significantly lower in pregnant subjects compared to the nonpregnant and showed a continuous significant decline with increasing duration of pregnancy. Mean hair concentration in the various stages of study of pregnant women and nonpregnant subjects were comparable. However, a progressive decrease in hair zinc concentration was noted with advancing pregnancy; the decline between 2nd and 3rd trimester was statistically significant. Mean serum zinc concentration in umbilical cord blood was approximately twice that in maternal blood. Smoking had no effect on zinc concentration, while the effect of alcohol and parity was inconsistent. Oral contraceptive usage before conception appeared to lower hair zinc concentration and increase serum zinc concentration during pregnancy. Two subjects had spontaneous abortion and these had serum zinc in the lower range and hair zinc values in the higher range. The remaining 58 subjects gave birth to normal neonates weighing 2500 to 4500 g. The study revealed that zinc nutrition of the majority of the expectant mothers was adequate for normal growth and development of fetus. The possible cause and implication of observed changes in zinc metabolism are discussed.