Associations between blood metals and fecundity among women residing in New York State

Trace exposures to metals may affect female reproductive health. To assess the relation between trace concentrations of blood metals and female fecundity, 99 non-pregnant women discontinuing contraception for the purpose of becoming pregnant were prospectively followed. Participants completed a baseline interview and daily diaries until pregnant, or up to 12 menstrual cycles at risk for pregnancy; home pregnancy test kits were used. For 80 women, whole blood specimens were analyzed for arsenic, cadmium, lead, magnesium, nickel, selenium and zinc using inductively coupled plasma mass spectrometry (ICP–MS). Time to pregnancy was estimated using Cox proportional hazards models for discrete time. Metal concentrations were generally within population reference intervals. Adjusted models suggest a 51.5% increase in the probability for pregnancy per 3.60 μg/L increase in Mg (P = 0.062), and a 27.7% decrease per 0.54 μg/L increase in Zn (P = 0.114). Findings indicate that Mg and Zn may impact female fecundity, but in varying directions.

Research highlights▶ Certain metals are required for reproduction at trace concentrations. ▶ Certain metals are reproductive toxicants at high dose, and may be so at low dose. ▶ Decreased female whole blood magnesium concentrations may decrease human fecundity. ▶ Increased female whole blood zinc concentrations may decrease human fecundity. ▶ Studies of environmental risk factors and health should assess a mixture of exposures.