Enhanced iodine concentrating capacity by the mammary gland in iodine deficient lactating women of an endemic goiter region in Sicily.

Iodine balance during pregnancy and lactation was investigated by measuring iodine concentration in the urine of 11 pregnant women, born and living in a moderately iodine deficient endemic goiter area in Northeastern Sicily, collected during the last week of pregnancy, and between the 5th and 7th day after delivery, and in their milk sampled simultaneously with the urine of their newborns. The results were compared with those obtained on similar samples from 16 euthyroid age-matched nongoitrous women and their offspring from an iodine sufficient area. Urinary iodine concentration in pregnant women from the endemic area (1.28 +/- 0.13 micrograms/dl, mean +/- SE) was significantly lower than that of pregnant women from the iodine sufficient area (3.77 +/- 0.57 micrograms/dl) (t = 3.56, p less than 0.005). The longitudinal measurement of iodine concentration in each nursing woman showed a marked increase (approximately 90%) when compared with the values obtained during pregnancy in both endemic and control groups (2.32 +/- 0.36 and 7.76 +/- 2.08 micrograms/dl; t = 2.13 p less than 0.05, respectively). The slight difference in milk iodine concentration between the endemic (3.25 +/- 0.77 micrograms/dl) and the control (4.33 +/- 0.57 micrograms/dl) group was not statistically significant (t = 1.14; p less than 0.5, NS). Similarly no difference was found in urinary iodine excretion between the endemic and the control newborn groups (3.41 +/- 0.76 and 4.30 +/- 0.65 micrograms/dl, respectively, t = 0.88 p less than 0.1, NS).(ABSTRACT TRUNCATED AT 250 WORDS)