Iodine is an essential micronutrient vital for
normal growth and development. When the iodine requirement is not met, growth
can be impaired. This micronutrients' requirement is increased during pregnancy
as it is important for prenatal and postnatal growth.
If the requirement is not met, it results in iodine
, which affects the thyroid
function of the mother, fetus and the mental development of the child born to
iodine -deficient mother. Iodine deficiency causes enlargement of the
thyroid gland known as goiter.
Studies have shown that iodine deficiency during
pregnancy results in stunted growth and neuromotor,
intellectual, behavioral, and cognitive impairment. Iodine supplementation
and iodized salt
help prevent iodine deficiency disorders in children.
Iodine deficiency is the cause of preventable brain
damage and mental retardation
in children. The
damage increases with the extent of the iodine deficiency.
Iodine for Prenatal Growth
Iodine plays a crucial role in the fetal
development. It is required for the synthesis of thyroid hormone, which is an
essential component for normal brain development during fetal and
early post-natal life. Iodine also helps to protect babies from
certain environmental harms.
The fetal brain development is maximum during the
first to second trimester, which is third to the fifth month of pregnancy.
During this period neural multiplication, migration and myelinization
take place at different sites in the brain, such as the visual and auditory cortex,
cerebral cortex and neocortex, hippocampus and cerebellum. This development is
dependent on maternal thyroxine sources as the fetal thyroid function is
Studies have shown that correction of
iodine deficiency during second trimester reduced neurological disturbances and
increased fetal head growth.
Iodine for Expectant Women
Pregnancy increases the demand of thyroid
hormones to meet the necessary requirements for normal fetal development. The
fetal thyroid is inactive until the 20th
week of pregnancy and
therefore is completely dependent on the maternal thyroxine supply. Thus the
maternal thyroid produces 1.5 fold more thyroxine. This increases iodine
requirement, which is the principle substrate for thyroid hormone synthesis.
During pregnancy iodine deficiency
has negative and irreversible effects on the developing fetus.
Most of the women are
marginally iodine deficient. Only 15 to 20 percent of pregnant and lactating
women are consuming iodine supplements. Most of the vitamin supplements taken
during pregnancy do not contain adequate amounts of iodine.
The Indian recommended
dietary allowance (RDA) for iodine intake in pregnant and lactating women is
200 mcg a day. Pregnant and lactating women should be advised to take vitamin
supplements with adequate iodine.
However, there is an upper safety
limit for iodine supplementation. Taking more than the recommended dietary
intake of iodine increases the risk for thyroid dysfunction
in pregnant and lactating
Iodine for Postnatal Growth
neonates, the recommended iodine intake is reflected from the mean intake of
iodine in the form of breast milk. However, the iodine content of breast milk
is influenced by the dietary intake of the pregnant and lactating women. In
postnatal life, thyroid hormones help regulate metabolic processes and
maturation of cardiac, pulmonary, bone and central nervous system.
deficiency during pregnancy has a long-term effect as it affects the subsequent
postnatal period as well. Postnatal iodine deficiency is linked to neurological
and cognitive function deficits.
deficiency contributes to reduced school performance, intellectual ability and
work performance. According to
a study, children born to women with
mild-to-moderate iodine deficiency during pregnancy are at increased risk for
lower IQ and reading ability by the time they turned 9 years.
Iodine supplements can help
prevent the risks associated with iodine deficiency. Studies have shown that iodine supplementation among school children has significantly
improved cognitive and motor performance.
Pregnant and lactating women can increase their
iodine levels by eating enough dairy products and sea foods. Universal salt
iodization is one of the best strategies to prevent neurodevelopment disorders
related to iodine deficiency. But most salt consumed by people comes from processed
foods, which is prepared with salt that is not iodized. Nowadays, sea salt and
kosher salt are most commonly used, which does not contain iodine.
Iodine deficiency is the leading preventable cause
of mental impaired function that affects as many as 2 billion people.
Prevention of iodine deficiency is possible, provided that the daily iodine
requirement to the mother is ensured, before and throughout the pregnancy
period as well as during lactating period.