Impact of maternal subclinical hypothyroidism on the neurocognitive development of children; a systematic review

Thyroid hormones play an important role in the development and maturation of the central nervous system before and after birth. There is not enough scientific evidence about the effect of subclinical hypothyroidism on neurocognitive development in offsprings. This systematic review was conducted to assess the effect of maternal subclinical hypothyroidism on the neurocognitive development of children.

In this systematic review, the PubMed, Web of Science, and Scopus databases as well as SID, Irandoc, and Magiran (Persian databases) were searched for the English and Persian related articles using appropriate keywords. In the current systematic review, of 411 records obtained through primary searching, 9 eligible cohort studies were evaluated. The quality of articles was assessed using the Newcastle-Ottawa scale.

Different studies have used different scales to evaluate the neurodevelopment of offsprings with different age ranges at the time of assessment. The results of 5 of the 9 selected studies indicated a lower IQ and neurodevelopment scores in the children born to mothers with subclinical hypothyroidism than in those born to euthyroid mothers. In four studies, there was no difference in neurodevelopment scores in the offsprings between the two groups.

There is no consensus about the impact of maternal subclinical hypothyroidism on neonatal neurodevelopment. Considering the limitations of the current methods for assessment of neurocognitive development of children, the use of new biochemical parameters for precise and early evaluation of neurocognitive development in offsprings should be taken into consideration.