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Guidelines needed to address iodine supplementation in pregnancy
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Despite routine recommendation of prenatal multivitamins before conception, pregnancy and lactation, many obstetricians and midwives fail to recommend iodine supplementation or to recommend an adequate amount.
“This failure to recommend iodine supplementation routinely may be due to the absence of specific guidelines of some obstetrical and midwifery societies, including the American Congress of Obstetricians and Gynecologists and the [American College of Nurse-Midwives], and to a lack of knowledge about the iodine status of U.S. pregnant women,” the researchers wrote.
Lewis E. Braverman, MD, professor of medicine in the section of endocrinology, diabetes and nutrition, Boston University School of Medicine, evaluated 199 midwives who were members of the American College of Nurse-Midwives and 277 obstetricians who were members of the AMA to determine their awareness of iodine nutrition and clinical practice regarding iodine supplementation.
“There is evidence that the major cause worldwide of a decrease in IQ is a lack of iodine during pregnancy,” Braverman told Endocrine Today. “The societies that are most involved with the care of pregnant women should emphasize that vitamins should be prescribed that contain iodine.”
Among obstetricians, 34.8% believed the iodine status of U.S. pregnant women was deficient, 46.7% believed it was adequate and 13% did not know. Results among midwives were similar, with 43.4% reporting iodine status as deficient, 32.1% as adequate and 15.3% did not know. Two-thirds of both groups reported that inadequate iodine status may result in adverse effects in the fetus; 60% of both groups reported iodine supplementation was useful for pregnant women and women of childbearing age.
More than 90% of both groups would recommend prenatal multivitamins for women planning pregnancy, pregnant women and lactating women, whereas iodine-containing prenatal multivitamins were recommended less often during preconception (68.7% of obstetricians; 70.2% of midwives), pregnancy (66% of obstetricians; 67.1% of midwives) and lactation (68.7% of obstetricians; 71.7% of midwives).
Forty-five percent of participants who would recommend iodine supplementation would recommend 150 µg, whereas 75% of all participants would not recommend supplementation or would recommend inadequate amounts.
“Doctors and midwives should be more aware of the need for extra iodine during pregnancy and lactation,” Braverman told Endocrine Today. “We were amazed, after all of the publicity that has been going on in the medical community and the endocrine community about the necessity for extra iodine and lactation for the welfare of the baby and fetus that the vast majority don’t recommend supplementation. Unless physicians prescribe prenatal vitamins with iodine or make sure the ladies are taking it, it is unknown. I think that the patient should bring in their bottle of vitamins and doctors should check the label to see if they contain iodine or not.” – by Amber Cox
For more information:
Lewis E. Braverman, MD, can be reached at lewis.braverman@bmc.org.
Disclosure: The researchers report no relevant financial disclosures.
Perspective
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Various guidelines from large international medical societies recommend the prenatal and perinatal use of multivitamins containing iodine. However, those societies formed by midwives and obstetricians (that is, those that see the majority of women before conception and during pregnancy) do not. In line with this, the study by De Leo and colleagues convincingly shows that the large majority (roughly 70%) of U.S. obstetricians and midwives do not specifically recommend the use of iodine-containing vitamins for women planning pregnancy, pregnant women or lactating women. The results from the current study are in line with results from (smaller) studies in other countries and highlight the need for better alignment between clinical practice recommendations from different medical societies. What interested me the most is the large gap between specific iodine recommendations and more standard recommendations with regard to prenatal and perinatal multivitamin use, as the latter was routinely recommended by more than 95% of all respondents. Researchers and medical doctors have known for a very long time that maternal iodine deficiency can have major consequences for the developing fetus, particularly brain development. Similarly, we know that a maternal lack of folic acid leads to neural tube defects, yet folic acid supplementation is widely recommended and iodine supplementation is not. One reason for this is that neural tube defects lead to a much more obvious phenotype than when a child is not reaching its full neurocognitive potential. It is much harder to prove an association with the latter than the former in a research setting, yet the iodine field has been able to do so. The only thing we lack in the iodine field are large randomized controlled trials showing the beneficial effects of iodine, which are there for other fields.
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