Postpartum maternal hyperthyrotropinemia in an area in which iodine supplementation is required

Mild maternal hypothyroidism during pregnancy can adversely affect infant development. We studied thyrotropin (TSH) levels in mothers of premature and low-birth-weight infants in Colombia, where iodized salt supplements the diet to correct iodine deficiency. The additional impact of salt restriction in mothers with hypertensive disorders was examined. Blood was spotted on filter paper from 404 mothers and their infants. Using radioimmunoassay (RIA), TSH was measured in the mothers, and TSH and thyroxine in their infants at three postpartum times. Initially, mothers had high TSH levels (i.e., TSH > 10 mU/L in half the mothers at the first assessment). Fourteen days later, only 9.3%, and at calculated term 7.5% were greater than 10 mU/L. Maternal TSH levels correlated with infant birth weight and gestational age (r = 0.47, and r = 0.49, p < 0.01). Initial TSH values were higher in salt restricted (20.1 +/- 2 mU/L, n = 76) versus control mothers (14.6 +/- 0.85, n = 328, p < 0.01), dropping dramatically in both groups 14 days later (to 3.4 +/- 0.7 mU/L vs. 2.8 +/- 0.4 mU/L) and at calculated term (2.8 +/- 0.4 mU/L vs. 2.3 +/- 0.6 mU/L). Increased maternal TSH levels during pregnancy in an iodine-deficient area may be aggravated by salt restriction. Monitoring TSH and supplementing iodine or thyroxine are recommended in pregnancy, especially if dietary salt restriction is prescribed.

Longitudinal assessment of pituitary-thyroid axis and adrenal function in preterm infants raised by 'kangaroo mother care'

OBJECTIVE

To assess whether complete kangaroo mother care (KMC), a skin-to-skin contact intervention, would affect longitudinal/developmental patterns of hormonal change.

METHOD

An open randomized controlled trial was conducted in a large tertiary care hospital, comparing KMC and traditional care for newborn infants weighing less than 2,001 g. Eighty-seven healthy preterm (<37 weeks gestational age) infants from this study provided three blood-spot samples on filter paper: at randomization (postnatal age 1-5 days), 2 weeks later, and at calculated term (41 weeks gestational age). They met a number of additional inclusion criteria including discharge from the hospital within the first postnatal week. The levels of 17alpha-hydroxy-progesterone (17-OHP), thyroxine-stimulating hormone (TSH) and thyroxine (T(4)) were assessed by radioimmunoassay. Birth weight (<1,800 or > or =1,800 g) and prenatal maternal corticosteroid treatment were taken into account in the analysis.

INTERVENTIONS

Complete KMC includes early discharge, positioning the infant on the parent's chest in an upright position, 24 h/day in skin-to-skin contact, and breast-feeding. In the traditional care group, infants were discharged according to routine hospital practice.

RESULTS

Levels of 17-OHP and TSH decreased significantly from eligibility to calculated term while T(4) levels did not change significantly over time. Most importantly, overall, treatment (KMC) did not interact with the pattern of physiological change.

CONCLUSIONS

Maturation of the pituitary-thyroid axis and adrenal function is apparently not compromised by KMC, at least in healthy preterm infants.