Iodine Metabolism and Thyroid Function During the Perinatal Period: Maternal-Neonatal Correlation and Effects of Topical Povidone-Iodine Skin Disinfectants

Abstract

An adequate maternal iodine intake during pregnancy and lactation is essential for growth and mental development in fetuses and newborns. Both de cient and excess iodine may disrupt normal thyroid function. There are limited data on perinatal iodine metabolism in mothers and infants, as well as the effect of povidone-iodine (PVP-I) antiseptics used in Cesarean delivery. The urinary iodine concentration (UIC), serum iodine, thyrotropin (TSH), free thyroxine (FT4) and breast milk iodine concentration (BMIC) were measured consecutively in a total of 327 mothers and 249 term-infants in two prospective studies.The maternal median UIC was 164 µg/L in the third trimester, increased to 256 µg/L on postpartum day 2, then decreased to 116 µg/L one month later. The BMIC on postpartum days 2 and 30 was 17.6 and 13.5 µg/100g, respectively. In neonatal infants born to the mothers unexposed to PVP-I, the median UIC was 131 µg/L in the rst voiding urine and increased to 272 µg/L on day 4, then slightly decreased to 265 µg/L on day 28 suggesting su cient iodine reserve at birth. PVP-I antiseptics containing 1g of iodine for skin preparation at Cesarean delivery transiently increase maternal serum iodine concentration, UIC and BMIC, however, it has little effect on maternal TSH, FT4 and neonatal UIC, TSH, or FT4. The iodine status of pregnant women and their infants was adequate in this population; however, the UIC in lactating mothers at one postnatal month was low enough to suggest iodine de ciency or near iodine de ciency. Further studies are necessary.This study was not registered to any clinical trials registry (CTR).

Prevalence of high neonatal thyroid stimulating hormone levels as an indicator of iodine deficiency in the province of La Pampa: An epidemiological analysis

“…These factors include the use of iodine antiseptics during delivery, preterm birth, low BW, male sex, and days of life at the time of sample collection. 11,20,21 This study found a higher prevalence of nTSH levels ≥ 5 mIU/L among term newborns than preterm newborns. These findings are consistent with research describing a higher incidence of thyroid dysfunction among preterm newborn infants, especially extremely preterm infants, due to the immaturity of the hypothalamic-pituitary- thyroid axis.…”

Prevalencia de hipertirotropinemia neonatal como indicador de deficiencia de yodo en la provincia de La Pampa: un análisis epidemiológico

“…Entre estos factores, se incluyen el uso de antisépticos yodados durante el parto, los nacimientos prematuros, el bajo PN, el sexo masculino y los días de vida al momento de la toma de la muestra. 11,20,21 En este estudio, se observó una mayor prevalencia de TSHn ≥5 mUI/l en nacidos a término en comparación con prematuros. Estos hallazgos coinciden con investigaciones que describen una mayor incidencia de disfunción tiroidea en los prematuros, especialmente en los extremos, debido a la inmadurez del eje hipotálamo-hipófiso-tiroideo.…”

Prevention of oral cross-infection by using povidone-iodine compared with other antiseptic agents for orally transmitted diseases: A Review

“…Therefore, to reduce the risk of neonatal hypothyroidism, healthcare and dental hygiene professionals should carefully consider the advantages and dangers and use caution when prescribing or suggesting povidone-iodine or any antiseptic agent to pregnant persons. (33) 8.…”