What Future Mothers and their Doctors need to know.

Maternal Thyroid Disease can have adverse impact on pregnancy outcome, and child development.

60% of pregnancies in the USA are unplanned, and 16% do not receive prenatal care until the second trimester. 4% have no prenatal care!

Although iodine intake was adequate in the USA, it has dropped in half since the 1970's, (300mcg/day to 160 mcg/day now). However 15-45 year old women have 5-12% chance of being below 50mcg/day. That is iodine deficiency. Many may be marginally deficient at 100mcg/day.

This is important, as the iodine needs increase to 225mcg/day during pregnancy. Prenatal vitamins do not usually contain iodine in the US. What to do? Well if you do take prenatals, you need to add iodine. 150mcg supplement will cover the gap. It is easier to take a regular multivitamin with iodine, and add extra 400mg folate. This will mimic the prenatals, but include added iodine you need.

In conclusion:

1. Iodine intake has declined from 1970 high of 300 mcg/day to 160 mcg/day.
2. Mild to moderate restriction of iodine intake may be present in 4-8% of young female population.
3. The recommended iodine intake increases in pregnancy to 225 mcg/day.
4. Multivitamins with iodine are recommended.
5. Beware that prenatals may not have iodine.
6. Adding 400 mcg of folate to an iodine containing multivitamin will mimic prenatals, but add iodine.

What happens to pregnant women who have thyroid dysfunction?

6-12% of child bearing age women have thyroid antibodies. 1-2.5% pregnant women have subclinical hypothyroidism (SCH). 0.3-0.5% have clinical hypothyroidism (CH), undiagnosed before pregnancy. Of 17,000 pregnant women enrolled in a clinic before 20 weeks gestation, 2.5% had (elevated TSH, 90% had normal FT4 subclinical hypothyroidism) , and 10% had clinical hypothyroidism with low FT4 and high TSH.

The frequency of obstetrical complications in women with SCH, or CH. The main complications are:

1. Increased miscarriage rate
2. Gestational Hypertension
3. Preterm delivery

Our USC thyroid expert Dr. Mestman, showed what happens to mothers who are hypothyroid with pregnancy. 143 hypothyroid pregnant women where reviewed. 11/143 were new cases, 35/143 where known , but stopped the hormone. 40/143 where inadequately replaced. They had marked increase in gestational hypertension, and prematurity. Outcomes were worse if the thyroid was not replaced to normal during the rest of the pregnancy.

Dr. Reed Larsen has shown that T4 requirements increase 50% by 6 weeks gestation. Thyroid function needs to be monitored through the end of the second trimester.

What about screening? Universal screening is not feasible, but identifying high risk women. 1. Infertility 2. Previous miscarriage 3. Diabetes 4. Juvenile Thyroiditis 5. Autoimmune Thyroiditis in close relatives.

The 4 clinical thyroid conditions

1. Clinical hypothyroidism CH
   
   Active Therapy with LT4
   
2. Subclinical Hypothyroidism SCH
   
   Active Therapy with LT4 is also warranted.
   
3. Thyroid autoantibodies with normal T4, and TSH.
   
   These women usually go into SCH or CH during the pregnancy.
   
   However, they can be found only by antibody\ screening.
   
   Referral of euthyroid women with positive antibodies to an thyroidologist, or endocrinologist is your best bet now, without a screening program in place.
   
   Voluntary screening by women who elect to pay for T4, TSH, and Antibody screening.
   
4. Neuropsychological performance of the offspring
   
   Lower global I.Q. with maternal hypothyroidism in the late gestation with elevated TSH. Still needs more research
   
   Cognitive Defects (poor visual performance, delayed response to various stimuli), are related to early TSH elevations. Still needs more research.
   
   Early and late TSH elevations are a problem in pregnancy. That is a fact. Exact details need more research.
   
   Also low birth weight, and smaller head size, are due to inadequate T4 transfer from the mother, in hypothyroid mothers. Still needs more research.

Summary:
The fact that many women are undiagnosed for several
years before diagnosis, could be a major component
in the impaired brain effects noted in hypothyroid
mother's offspring.

Reference:
www.hotthyroidology.com

Future Mothers:
Know your family history, make sure you get enough iodine supplements, and get tested if you know you have thyroid disease. Also see a thyroidologist, if you have thyroid antibodies, but normal T4 and TSH. For those who can afford to pay, get screened!

Yours truly, and goodbye,