[Association of related maternal factors with susceptibility to congenital hypothyroidism: a case-control study]

To study the association of related maternal factors with the susceptibility to congenital hypothyroidism (CH) in neonates.

A case-control study was designed. The neonates who were diagnosed with CH in Neonatal Screening Center of Henan Province from January 1, 2016 to December 31, 2017 were enrolled as cases. Healthy neonates, matched for sex and age were enrolled as controls. A conditional logistic regression analysis and additive and multiplicative interaction analyses were used to identify the risk factors for susceptibility to CH.

A total of 2 771 661 neonates were screened during this period, among whom 1 494 neonates were diagnosed with CH, with a crude incidence rate of 53.9/100 000. A total of 843 pairs of the cases and the controls completed the telephone survey and provided qualified data. The conditional logistic regression analysis showed that an older maternal age at delivery, a low educational level in mothers, living in the rural area, a family history of thyroid diseases, histories of exposure to formaldehyde during pregnancy, exposure to radiation during pregnancy, and medication during pregnancy, were risk factors for CH (P<0.05), while low maternal age at delivery and progesterone intake during pregnancy were protective factors against CH (P<0.05).

An older maternal age at delivery, a low educational level in mothers, living in the rural area, a family history of thyroid diseases, and histories of exposure to formaldehyde during pregnancy, exposure to radiation during pregnancy and medication during pregnancy may increase the susceptibility to CH in neonates.