Post on 04-Jan-2016
description
THYROID DISEASE THYROID DISEASE IN IN
PREGNANCY:PREGNANCY:TREATING TWO TREATING TWO
PATIENTSPATIENTS
Susan J. Mandel, MD MPHSusan J. Mandel, MD MPH
Perelman School of Medicine, Perelman School of Medicine,
University of PennsylvaniaUniversity of Pennsylvania
Outline
• Background• Importance of thyroid hormone
during pregnancy• Hypothyroidism during pregnancy• General population of women in
the child bearing years
Thyroid gland
• Thyroid hormones—made from IODINE– Thyroxine (T4)– Triiodothyronine (T3) MOSTLY made in liver
• Many targets in the human body• Synthetic T4 (LEVOTHYROXINE LT4)
readily available
The importance of thyroid hormone for normal growth and development
Cretinism• Due to severe dietary iodine
deficiency• Severe hypothyroidism in
BOTH Mom and fetus• Impaired cognitive
development• Poor growth• Iodine deficiency is
considered the most common cause of preventable brain damage in the world today (WHO 1994).
http://www.thyroidmanager.org/Chapter20/index.html
Sources of thyroid hormone for the fetus
• Mom: Thyroid hormone crosses the placenta starting in 1st trimester
• Fetus: Thyroid begins to function at 12 weeks gestation
And if the baby’s thyroid doesn’t work. . . .
• Congenital hypothyroidism affects 1:3000 live births in the US
• Newborn screening programs in all 50 states
• Detection and treatment by 1 month of life results in normal outcomes
• THEREFORE, maternal thyroid hormone can protect fetal development in utero
What if the mom’s thyroid doesn’t work?
• “Hypothyroidism” – Hashimoto’s thyroiditis– Prior ablation with radioactive iodine– Prior thyroid surgery
• Detected by a blood test (TSH)• Spectrum
– Mild “subclinical” hypothyroidism 1:50 pregnancies
– Severe “overt” hypothyroidism 1:500 pregnancies
Subclinical OvertHypothyroidism
Spontaneous abortion5,7 10-70% 60%Preeclampsia1,2,4,6,9 0-17% 0-44%Abruption2,3,4,6,7 0% 0-19%Stillbirth/fetal loss1,2,3,6 0-3% 0-12%Anemia2,3 0-2% 0-31%Postpartum hemorrhage2,3,4 0-17% 0-19%Preterm birth2,3,7,8 0-9% 20-
31%1Montoro et al, Ann Intern Med 1981; 2Davis et al, Obstet Gynecol 1988; 3Leung et al, Obstet Gynecol 1993; 4Wasserstrum et al, Clin Endocrinol 1993; 5Glinoer, Thyroid Today, 19956Allan et al, J Med Screen 2002; 7Abalovich et al, Thyroid 2002; 8Stagnaro-Green et al, Thyroid, 2005; 9Sahu et al, Arch Gynecol Obstet 2009
““Maternal hypothyroidism is associated with Maternal hypothyroidism is associated with increased rate of pregnancy complications, and increased rate of pregnancy complications, and the risk is greatest in overt hypothyroidism the risk is greatest in overt hypothyroidism compared to subclinical hypothyroidism.”compared to subclinical hypothyroidism.”
LaFranchi, Thyroid 2005
What if the mom’s thyroid doesn’t work? ~2% of all pregnancies
For hypothyroid women taking levothyroxine (LT4) who become
pregnant• Increased LT4 dosage required in
majority of woman• Average dose increase about 30%• TIMING for increase as early at 7-8 weeks
gestation USUALLY prior to 1st OB visit• TSH monitoring required during
pregnancyOne option: take two additional LT4 pills/weekOne option: take two additional LT4 pills/week
Yassa J Clin Endocrinol Metab 2010 95:3234
And, we are still not getting it right . . .
Abnormal thyroid function tests in Abnormal thyroid function tests in pregnant hypothyroid women taking LT4pregnant hypothyroid women taking LT4
43
3328
05
101520253035404550
Frequency
(%
)
1st trimester 2nd trimester Both trimesters
McClain, Am J Obstet Gynecol 2008
n=389
2011 Guidelines: Endocrine Society
American Thyroid Association
• Pre conception education of hypothyroid women and optimization of LT4 dosage
• Check thyroid function tests as soon as pregnancy confirmed and consider empirically increasing LT4 dose by taking 2 additional LT4 tablets per week
Thyroid health in pregnant women without thyroid disease
• Daily iodine requirements increase in pregnancy – WHO 250mcg/day– Institute of Medicine 220mcg/day
• NOT all prenatal vitamins contain iodine!• In the USA, as of 2009, only 51% of In the USA, as of 2009, only 51% of
prenatal vitamins labeled to contain prenatal vitamins labeled to contain iodineiodine
• Measured iodine content was only 75% of Measured iodine content was only 75% of labeled content!labeled content!
Leung A et al N Engl J Med 2009 360:9
• All women attempting to conceive and pregnant women take a prenatal vitamin containing 150mcg of potassium iodine
2011 Guidelines: Endocrine Society
American Thyroid Association
Screening• Prevalent disease• Screening test for disease identification• Adverse outcome related to disease• Therapy that ameliorates outcome
Screening: Thyroid disease in pregnancy
• Prevalent disease– YES--~2% of all pregnanciesYES--~2% of all pregnancies
• Screening test for disease identification– YES
• Adverse outcome related to disease– YES
• Therapy that ameliorates outcome– Therapy —YES– Outcome improved — so far NO
Recent Developments for Subclinical Hypothyroidism
2 prospective randomized controlled trials
MATERNAL HEALTHNegro R et al, Universal Screening vs Case Finding for Detection and Treatment of Thyroid Dysfunction During Pregnancy, J Clin Endocrinol Metabolism 2010 95:1699
FETAL HEALTHLazarus J et al. Controlled Antenatal Thyroid Screening (CATS) Study. 14th International Thyroid Congress, Sept 2010
Maternal Adverse Outcomes: Negro 2010
PRIMARY ENDPOINT:NO BENEFIT to pregnancy outcome
0.7 0.7
0
0.5
1
1.5
2
com
plica
tions/p
ati
ent
Universal Screen Case Finding
Cognitive development and Maternal Hypothyroidism
Courtesy of John Lazarus ITC 2010
Cognitive Development: CATS 2010
PRIMARY ENDPOINT:NO difference in IQ scores
100 99
0
20
40
60
80
100
120
IQ s
core
Universal Screen Control
What to doWhat to do
• However, secondary analyses for both studies suggest a benefit
• Negative results could be due to screening and intervention at end of 1st trimester—TOO LATE
• Insufficient evidence to recommend universal screening for thyroid disease in pregnant women
• Aggressive detection of women at high risk for thyroid dysfunction
2011 Guidelines: Endocrine Society
American Thyroid Association
Women at risk for hypothyroidism
• History of thyroid dysfunction or prior thyroid surgery
• Signs or symptoms of thyroid problem• Women older than age 30• Presence of other autoimmune disorders
– Type 1 diabetes, rheumatoid arthritis
• Family history of thyroid dysfunction• History of miscarriage or preterm labor
What is needed . . .• Education programs targeted to patients
and care providers– HYPOTHYROID PREGNANT patients: HIGHER
thyroid hormone doses– All women: IODINE containing prenatal vitamins
• Partnerships with public health, government and professional organizations to insure all prenatal vitamins contain 150mcg of potassium iodine
• Exploration of the feasibility of a randomized controlled trial that screens, identifies, and treats thyroid dysfunction in women PRIOR to conception
Thank you for your attention