Impact of maternal thyroid disease on neonatal thyroid status.

Objectives: Prevalence of Maternal and congenital hypothyroidism is on the rise. To present the thyroid stimulating hormone screening results in babies born to hypothyroid mothers and assess the burden, aetiology of hypothyroidism in these babies.

Methods: All antenatal mothers attending our hospital during the study period were enrolled into the study. Group I includes 249 term babies born to hypothyroid mothers and group II comprises 2154 newborns born to mothers who are euthyroid. Heel prick thyroid stimulating hormone was done for all newborns on day 3 for both groups. Confirmatory venous testing was done for all for babies in group I and screen positives belonging to group II. Evaluation and therapy done as per standard guidelines.

Results: Thyroid stimulating hormone values in the two groups are presented. There was significant correlation between peak maternal thyroid stimulating hormone and neonatal day 3 heel prick in group I (r=0.7, P<0.05). The prevalence of positive screening test in groups I and II was 3.8 and 1.03% (p<0.05) whereas corresponding values for confirmed disease was 4.3 and 0.6%, respectively (p<0.05). Aetiological evaluation revealed both transient hypothyroidism (33.3%) and permanent hypothyroidism (66.6%).

Conclusion: 4.3% of babies born to hypothyroid mothers develop congenital hypothyroidism; aetiology being both transient and permanent. A venous test by 3 weeks is helpful in these babies to improve case identification.