Title: Association of Neonatal Hypothyroidism and Low Birth Weight & Pre Term Babies
Authors: Indra.N, Sreekala K.N
DOI: https://dx.doi.org/10.18535/jmscr/v7i8.15
Abstract
Background and Rationale
Congenital hypothyroidism is the most common disorder identified by routine newborn screening. It is found in 1:3000 to 1:5000 screened infants (Dussault, 1993). The major clinical features of untreated congenital hypothyroidism are growth retardation and delayed cognitive development leading to mental deficiency. If treatment with pharmacologic doses of T4 is initiated early, growth and mental development are normal. Congenital hypothyroidism (CH) is the most common cause of preventable mental retardation in children. Thus screening programs of CH have been established for better management of the disorder and preventing its related neuro developmental consequences1.
The reported incidence rate of CH has significantly rise during past two decades. Suggested factors related to this high rate of CH occurrence are increased prevalence of CH and high rate of preterm infant births2,3.
Evidence from different screening programs indicated that the rate of CH was higher in pre-term and low-birth-weight (LBW) newborns than normal ones due to insufficient development of hypothalamic pituitary axis.4Prevalence of this condition in very-low-birth-weight (VLBW) infants with birth weight of less than 1500 g has been approximately measured as 1 in 400 cases, which is significantly higher than its prevalence in full-term infants (1 in 4000 cases); however, only one-third of these infants can be diagnosed using the screening program.5,6There-fore, it is critical to screen CH in preterm infant, to pre-vent and minimize neurodevelopmental impairment. Some studies suggest that screening in VLBW newborns should be repeated, whereas others recommended other strategies, including lowering screening TSH cutoff and etc.
References
- Sharon E. Oberfield What's birth weight got to do with it?The Journal of Pediatrics, Volume 178, 2016, p. 3
- Xiaoli Sun, Brigitte Lemyre, Xiaoqin Nan, JoAnn Harrold, Sherry L. Perkins, Sarah E. Lawrence, Nick Barrowman .Free thyroxine and thyroid-stimulating hormone reference intervals in very low birth weight infants at 3–6 weeks of life with the Beckman Coulter Unicel DxI 800 .Clinical Biochemistry, Volume 47, Issues 1–2, 2014, pp. 16-18
- Irit Schushan-Eisen, Liora Lazar, Nofar Amitai, Joseph Meyerovitch. Thyroid Functions in Healthy Infants during the First Year of Life. The Journal of Pediatrics, Volume 170, 2016, pp. 120-125.e1
- Murphy N, Hume R, van Toor H, Matthews TG, Ogston SA,Wu SY, et al. The hypothalamice pituitarye thyroid axis inpreterm infants; changes in the first 24 hours of postnatal life. J Clin Endocrinol Metab 2004;89:2824e31.
- Hunter MK, Mandel SH, Sesser DE, Miyabira RS, Rien L, Skeels MR, et al. Follow-up of newborns with low thyroxine and non elevated thyroid-stimulating hormone-screening concen-trations: results of the 20-year experience in the Northwest regional newborn screening program.J Pediatr 1998;132:70e4
- Woo HC, Lizarda A, Tucker R, Mitchell ML, Vohr B, Oh W, et al.Congenital hypothyroidism with a delayed thyroid-stimulating hormone elevation in very premature infants: incidence and growth and developmental outcomes. J Pediatr 2011;158:538e42.
- Lee JH, Kim SW, Jeon GW, Sin JB. Thyroid dysfunction in verylow birth weight preterm infants. Korean J Pediatr 2015;58:224e9.
- Muhammad Z, Irshad M. Comparison of serum TSH and T4 levelsin preterm and term neonates for screening of congenital hypothyroidism.J Med Sci (Peshawar) 2013;21:194e7.