Determination of zinc in amniotic fluid in normal and high risk pregnancies

The role of zinc in reproduction. Hormonal mechanisms

Zinc is a very important element in the reproductive cycle of species. In humans, it is necessary for the formation and maturation of spermatozoa, for ovulation, and for fertilization. During pregnancy, zinc deficiency causes a number of anomalies: spontaneous abortion, pregnancy-related toxemia, extended pregnancy or prematurity, malformations, and retarded growth. Delivery is adversely affected by deficiency. These different effects of zinc can be explained by its multiple action on the metabolism of androgen hormones, estrogen and progesterone, together with the prostaglandins. Nuclear receptors for steroids are all zinc finger proteins. Zinc supplementation has already proven beneficial in male sterility and in reducing complications during pregnancy. However, it would be worth conducting larger-scale trials to confirm these beneficial effects.

Amniotic fluid zinc in risk pregnancies

The zinc concentration of amniotic fluid (AF) of 129 pregnant women was analyzed by the flame atomic absorption spectrometry. This prospective study was performed in order to find out whether the determination of the AF zinc concentration can be used to monitor the growth and development of the fetus. There were two groups of patients: early stage (15th-19th gestation wk) in which the amniocentesis was performed as a prenatal genetic examination, and late stage (26th-40th wk) in which the amniocentesis was performed due to obstetric reasons. The average AF zinc concentrations were 1.2 and 1.0 μmol/L in the early and late gestation group, respectively. The AF zinc concentration did not correlate with the weight, height, or Apgar scores of the newborn nor with the maternal diseases, age, or parity. The AF zinc concentration in the late gestation group was significantly lower if the fetus was male than if it was female. If the AF was greenish the zinc concentration was elevated. One malformation, congenital nephrosis, with an exceptionally high zinc concentration (9.0 μmol/L), was found.