Congenital hypothyroidism with delayed thyroid-stimulating hormone elevation in premature infants born at less than 30 weeks gestation.

OBJECTIVE: Congenital hypothyroidism (CH) with delayed thyroid-stimulating hormone (TSH) elevation is a common form of thyroid dysfunction among premature infants. Routine newborn screening (NBS) may miss infants with CH with delayed TSH elevation. The objective of the study is to determine the prevalence of CH with delayed TSH elevation in premature infants and to identify associated risk factors. STUDY DESIGN: Retrospective analysis of serum thyroid function screening (TFS) at day of life 30 in premature infants <30 weeks gestation, admitted to University of Iowa Neonatal Intensive Care Unit between 1 July 2012 to 30 June 2015. Serum free thyroxine and TSH levels were obtained in premature infants <30 weeks gestation on day of life 30. Follow-up testing and pediatric endocrinology consultation were done according to the institutional protocol. RESULT: In total, 286 infants were included. All infants underwent routine NBS and 280 patients underwent TFS. Twenty-six patients (9.1%) were diagnosed with thyroid dysfunction. NBS identified only three patients. CH with delayed TSH elevation was diagnosed in 20 patients (6.9%) and was significantly associated with multiple gestation, lower birth weight, higher gestational age and lower 5 min APGAR score. CONCLUSION: Thyroid dysfunction is common among premature infants born before 30 weeks gestation. The majority of cases with thyroid dysfunction had CH with delayed TSH elevation, which was not detected by NBS. We recommend measurement of serum TSH and free T4 levels on day of life 30 in premature infants born at <30 weeks gestation to identify patients with CH with delayed TSH elevation.

Positive effect of NICU admission on breastfeeding of preterm US infants in 2000 to 2003.

OBJECTIVE: We hypothesized that neonatal intensive care unit (NICU) admission reduces breastfeeding in a recent population of US infants, adjusting for confounding factors. STUDY DESIGN: Using pregnancy risk assessment monitoring system data from 27 states for the years 2000 to 2003, we determined the relationship between breastfeeding and gestational age (GA) stratified by NICU status. We fitted a proportional odds model for breastfeeding duration as a function of NICU status adjusted for other covariates. SAS 9.1.3 and SUDAAN 9.0 were used for the weighted analyses. RESULT: In total 138 359 surveys, including 29 940 NICU-admitted infants, were analyzed. A total of 73% of mothers of nonadmitted infants initiated breastfeeding vs 70% of mothers of NICU-admitted infants. Mothers of GA <38 weeks NICU-admitted infants were 34% more likely to initiate breastfeeding and 21% more likely to breastfeed for 4 weeks than were mothers of nonadmitted preterm infants (P<0.001). However, mothers of term NICU-admitted infants were less likely to initiate and continue breastfeeding to 4 weeks than were mothers of term nonadmitted infants (P<0.001). Adjusting for GA, race, maternal age, maternal education, mode of delivery and Medicaid status, NICU admission was associated with increasing duration of breastfeeding (OR 1.10, CI 1.03, 1.17). Compared with mothers of term infants, mothers of <32-week infants were 40% more likely to continue breastfeeding for 4 weeks, mothers of 32 to 34 week infants were 13% less likely to continue and mothers of 35-37 week infants were 22% less likely to continue for at least 4 weeks (P<0.001). CONCLUSION: NICU admission is now a positive influence on breastfeeding continuation, improving the overall likelihood by 10%. Mothers of preterm NICU-admitted infants were more likely than mothers of nonadmitted infants to continue breastfeeding for 4 weeks, while mothers of term NICU-admitted infants were less likely to continue. Breastfeeding support should be enhanced for term and late preterm infants.