Iron status in women with infertility and controls: a case-control study.

Background: Iron deficiency is a common problem in subfertile women. The influence of iron status on unexplained infertility is unknown.

Methods: In a case-control study, 36 women with unexplained infertility and 36 healthy non-infertile controls were included. Parameters of iron status including serum ferritin and a serum ferritin <30 µg/dL served as main outcome parameters.

Results: Women with unexplained infertility demonstrated a lower transferrin saturation (median 17.3%, IQR 12.7-25.2 versus 23.9%, IQR 15.4-31.6; 0.034) and a lower mean corpuscular hemoglobin concentration (median 33.6 g/dL, IQR 33.0-34.1 versus 34.1 g/dL, IQR 33.2-34.7; 0.012). Despite the fact that there was no statistically significant difference in median ferritin levels ( 0.570), women with unexplained infertility had ferritin levels <30µg/L more often (33.3%) than controls (11.1%; 0.023). In a multivariate model, unexplained infertility and abnormal thyroid antibodies were associated with ferritin <30µg/L (OR 4.906, 95%CI: 1.181-20.388; 0.029 and OR 13.099; 2.382-72.044; 0.029, respectively).

Conclusion: Ferritin levels <30µg/L were associated with unexplained infertility and might be screened in the future. Further studies with a focus on iron deficiency and iron treatment on women with unexplained infertility are warranted.