Iodine and Fertility: Do we Know Enough?

Divya M. Mathews; Neil P. Johnson; Robert G. Sim; Susannah O'Sullivan; Jane M. Peart; Paul L. Hofman


Hum Reprod. 2021;36(2):265-274. 

In This Article

Could Iodine Deficiency Explain Some Cases of Unexplained Infertility?

The term 'iodine deficiency disorders' (IDD) comprises a spectrum ranging from subclinical hypothyroidism to endemic cretinism. Reduced fertility and impaired fetal development are listed among the many manifestations of iodine deficiency and hence are part of the IDD spectrum (Dunn and Delange, 2001). It is well known that deficiency of this trace element is associated with abortions, still births and congenital anomalies (Semba and Delange, 2008). More recently, Mills et al. (2018) conducted a study in over 500 women in the USA and found that those with lower urinary iodide levels had a 46% reduction in fertility. Moreover, women with low iodine levels also took longer to conceive, with 28% of the iodine deficient group failing to conceive at 12 months compared to only 12.5% in the iodine sufficient group. This suggests that iodine deficiency may contribute to a proportion of UI in developed countries (Mills et al., 2018). Another study in West Africa showed that women with iodine deficiency have twice the risk of reproductive failure and again, the risk of reproductive failure being directly proportional to the severity of iodine deficiency (Dillon and Milliez, 2000). While a recent prospective cohort study did not find an association between iodine deficiency and pregnancy losses (Mills et al., 2019), current data suggests that iodine plays an important role in conception and ongoing pregnancy.