Onal H et al. – In in vitro fertilization (IVF) babies, despite normal neonatal screening tests, subclinical hypothyroidism might be observed that suggests the need for screening in this respect.Methods
- A total of 98 healthy, term IVF newborns were evaluated between postnatal 2–4 weeks of age by screening of thyroid functions between July 2006 and April 2008.
- Ten subjects were assessed as a study group whose thyroid-stimulating hormone (TSH) levels were higher than 6.5 mU/L.
- Control group consisted of randomly selected 10 naturally conceived infants with hyperthyrotropinemia (whose TSH levels were higher than 6.5 mU/L but under 15 mU/L) with the same age.
- All children were thoroughly examined, and serum fT4, TSH, anti-thyroid peroxidase and anti-thyroglobulin antibodies were measured, and a thyrotropin-releasing hormone (TRH) test was performed in all subjects in both groups.
- Euthyroid hyperthyrotropinemia was diagnosed in approximately 10% of IVF babies.
- Exaggerated TSH levels to TRH were obtained in all IVF babies (subclinical hypothyroidism) but in none of the controls.
- A significant difference was noted in the concentration of TSH at the 20th min between the two groups (p < 0.001).
- Besides, sustained and delayed TSH responses were observed in IVF babies. Neonatal screening tests were negative in both of the groups.