Delayed conception in women with low-urinary iodine concentrations: a population-based prospective cohort study

Area of Science:

• Reproductive Health
• Nutritional Science
• Endocrinology

Background:

• Iodine deficiency is prevalent among women of reproductive age.
• The impact of iodine deficiency on fecundability (the ability to conceive) remains under-investigated.

Purpose of the Study:

• To investigate the association between iodine deficiency and fecundability in women attempting to conceive.
• To quantify the reduction in fecundability associated with varying levels of iodine deficiency.

Main Methods:

• A prospective cohort study (LIFE Study) involving 501 women trying to conceive.
• Urine iodine concentration analysis and daily fertility monitoring via journals and ovulation predictors.
• Pregnancy detection using home digital tests.

Main Results:

• 44.3% of participants exhibited iodine deficiency.
• Moderate to severe iodine deficiency (iodine-creatinine ratio < 50 μg/g) was linked to a 46% decrease in fecundability.
• The adjusted odds ratio for becoming pregnant per cycle was 0.54 (95% CI 0.31-0.94) in deficient individuals.

Conclusions:

• Iodine deficiency is associated with significantly reduced fecundability in women.
• These findings suggest that common iodine concentrations in the USA and Europe may delay conception.
• Further research is needed to confirm if improving iodine status can enhance fecundability.