The etiologies and incidences of congenital hypothyroidism before and after neonatal TSH screening program implementation: a study in southern Thailand

[Risk factors for neonatal congenital hypothyroidism: a Meta analysis]

OBJECTIVE

To investigate the risk factors for congenital hypothyroidism (CH) in neonates, and to provide a reference for the prevention of CH.

METHODS

The databases including China Biomedical Literature Service System, China National Knowledge Infrastructure, Wanfang Data, and Weipu Periodical Database, PubMed, Web of Science, Embase, SpringerLink, and Elsevier/ScienceDirect were searched for studies on the risk factors for CH in neonates published up to August 1, 2020. R 3.6.2 and RevMan 5.3 software were used to perform a Meta analysis.

RESULTS

A total of 20 studies were included, with 13 case-control studies and 7 cross-sectional studies. There were 11 564 neonates in total, with 3 579 neonates in the case group and 7 985 neonates in the control group. The Meta analysis showed that advanced maternal age (OR=2.111, 95%CI: 1.275-3.493), thyroid disease during pregnancy (OR=3.365, 95%CI: 1.743-6.500), gestational diabetes mellitus (OR=2.158, 95%CI: 1.545-3.015), anxiety (OR=3.375, 95%CI: 2.133-5.340), medication during pregnancy (OR=2.774, 95%CI: 1.344-5.725), radiation exposure during pregnancy (OR=3.262, 95%CI: 1.950-5.455), family history of thyroid disease (OR=8.706, 95%CI: 5.991-12.653), low birth weight (OR=2.674, 95%CI: 1.895-3.772), fetal macrosomia (OR=1.657, 95%CI: 1.187-2.315), preterm birth (OR=2.567, 95%CI: 2.070-3.183), post-term birth (OR=2.083, 95%CI: 1.404-3.091), twin pregnancy or multiple birth (OR=3.455, 95%CI: 1.958-6.096), and birth defects (OR=6.038, 95%CI: 3.827-9.525) were risk factors for CH in neonates.

CONCLUSIONS

Advanced maternal age, gestational thyroid disease, gestational diabetes mellitus, anxiety, medication during pregnancy, radiation exposure during pregnancy, family history of thyroid disease, low birth weight, fetal macrosomia, preterm birth, post-term birth, twin pregnancy or multiple pregnancy, and birth defects may increase the risk of CH in neonates.

Congenital hypothyroidism in preterm infants: a 3- to 8-year longitudinal study in southern Thailand

Background Preterm infants are at high risk of developing congenital hypothyroidism (CH) due to the immaturity of the hypothalamic-pituitary-thyroid (HPT) axis, loss of iodine supply from the mother and preterm health problems. Objectives To study the incidence and etiologies of CH in preterm infants who were born or admitted in our institute during 2010-2015. Methods The medical records of preterm infants diagnosed with CH as defined by the thyroid-stimulating hormone (TSH) level at the time of the first or second screening >10 mU/L and/or free T4 < 1.00 ng/dL were reviewed. Results Of 2777 preterm infants, 73 cases (2.6%) were diagnosed as CH. The average TSH levels at the first and second screenings were 20.85 and 15.42 mU/L, respectively. The patients were treated with thyroxine at an average initial dosage of 15 μg/kg/day. At 2-3 years of age, after thyroxine discontinuation for 6-10 weeks and regular thyroid function tests for 2 years, 58 patients (79.5%) were diagnosed as having transient CH and 15 patients (20.5%) were diagnosed as having permanent CH. We found no clinical or laboratory parameters in the neonatal period that could differentiate permanent from transient CH. Thyroid scintigraphy (99 m pertechnetate) revealed two patients (13.3%) with ectopic thyroid, one with thyroid hypoplasia (6.7%), eight with normal thyroid (53.3%) and four with enlarged thyroid (26.7%). Conclusions CH was common in preterm infants with an estimated incidence of 2.6%. Thyroxine should be given to preterm infants with higher initial values of TSH >10 mU/L in order to prevent delayed treatment of permanent CH that could be confirmed later.

Newborn screening in the developing countries

PURPOSE OF REVIEW

We review newborn screening (NBS) publications from the developing countries to identify global progress in improving child health.

RECENT FINDINGS

Many developing countries do not yet have national NBS. As infant mortality rates decline, NBS gains in public health priority. Local incidence and outcome data are used to persuade health officials to include screening in priority health spending. Congenital hypothyroidism is the most cost-effective screened condition in most countries. In sub-Saharan Africa, India and some parts of Asia, screening for hemoglobinopathies and glucose-6-dehydrogenase deficiency are also important. Expanded screening for metabolic conditions is most needed in areas of high consanguinity. Screening for hearing disorders and critical congenital heart defects is increasing globally. The largest birth cohorts are India and China, but only China has successful NBS. Reports from completed government research projects in India support initiation of NBS.

SUMMARY

Government activities around NBS are increasing in India and there is increased emphasis on pilot programs for sickle cell NBS in sub-Saharan Africa. Genetic counseling training in Asia and Africa is increasing and will be helpful as part of NBS. To build successful screening programs, partnerships among health professionals, parents, policy makers and industry stakeholders are essential.