Prevalence of congenital hypothyroidism in infants of mothers with hypothyroidism: a meta-analysis

The prevalence of congenital hypothyroidism (CH) in infants of mothers with hypothyroidism has been described but a comprehensive prevalence estimation is lacking. The comprehensive analyses of subtyping, quantum of excess risk in comparison to those born to euthyroid mothers and association with thyroid antibodies are also lacking. This systematic review and meta-analysis aimed to estimate the pooled prevalence of CH in infants born to mothers with hypothyroidism. PubMed database was searched from inception to February 2025 using the search terms' ((congenital hypothyroidism) and (maternal hypothyroidism)) or (mothers with hypothyroidism)'. Of 2097 initially identified articles, 18 met inclusion criteria, encompassing 11,242 infants of mothers with hypothyroidism. CH diagnoses were classified as transient (TCH) or permanent (PCH). The overall pooled prevalence of CH among infants of mothers with hypothyroidism was 0.003767 (95 % CI: 0.001796-0.005637). TCH accounted for Prevalence of TCH was 0.001867 (95 % CI: 0.000674-0.003060) whereas that of PCH was 0.001429 (0.000386-0.002473). Infants of hypothyroid mothers exhibited significantly increased risk of CH (OR: 3.48, 95 % CI: 1.25-9.65) than those of euthyroid mothers. Maternal thyroid antibody status (TPOAb positivity) did not significantly influence CH prevalence (OR: 0.97, 95 % CI: 0.19-4.81). In conclusion, infants of mothers with hypothyroidism have a substantially higher prevalence (1 in 265) than that reported in the general population. The risk was also 3.5 times higher in the systematic review. However, no association between maternal thyroid antibodies and CH was observed, emphasizing a need to explore alternative pathogenetic mechanisms.