thyroid

1. Thyroid disorder in pregnancy
Presented
by
Dr. Syeda Trina
Intern Doctor
Deartment of Mdicine
Unit Blue
M Abdur Rahim Medical
College,Dinajpur

2. -Clinical features:
-Weight increase
-Sensitivity to cold
-Dry skin
-Asthenia
-Drowsiness
-Constipation-

3. Definition of hypothyroidism
nonpregnants:
Normal TSH (0.5-5 mlU/I)
Overt Hypothyroid (OH):
• TSH >5 mlU/l and FT4: Low
Sub-Clinical Hypothyroid (SCH):
• TSH:>5 mlU/I, FT 4 : Normal

4. Definition of Hypothyroidism
Pregnancy
Overt Hypothyroid (OH) :
• TSH >2.5 mlU/ and FT4: Low
• TSH 210mlU/l irrespective of FT4 value .
• Normal upper limit -<4 miu/l (2017) .
Sub-Clinical Hypothyroid (SCH):
• TSH: 2.5 to 10 mlU/I, FT 4: Normal.

5. Prevalence of Thyroid
autoantibodies
• Thyroid autoantibodies : 5 % - 15 % in child
bearing age .
• Associated with increased rate of pregnancy loss.
• Chronic autoimmune thyroiditis is the leading
cause of hypothyroidism in pregnancy.
• lodine deficiency (UIE < 10 µg/dl) by WHO.

8. lodine Requirement in
pregnancy
WHO recommends- 250µg /d to
compensate
Increase in thyroxine requirement
 Increase renal lodine loss
 Increase fetal lodine requirement

12. Trimester specific TSH level
If trimester specific TSH level is not
available in laboratory following ref.
range is recommended by (ATA 2011
endo soc 2012)
• First trimester 0.1-2.5 mlU/I
• Second trimester 0.2-3.0 mlU/I
• Third trimester 0.3-3.0 mlU/I

13. Screening during Pregnancy
• Targeted case finding vs. universal screening.
• Guideline by ATA,AACE, ACE - Screen only
high risk one.
Different studies revealed up to 30% cases
missed in high risk screening, and thus
universal screening is more prudent.

14. High risk
1.History of hyperthyroid or hypothyroid
disease, PPT, or thyroid lobectomy.
2. Family history of thyroid disease.
3. Women with a goiter.
4. Positive thyroid antibodies .
5. Symptoms or clinical signs suggestive of
hypo or hyperthyroidism.

15. 6. Type 1 diabetes.
7. Presence of other autoimmune disorders. 8.
Infertility who should have screening with TSH as
part of their infertility work-up.
9. Previous therapeutic head or neck irradiation.
10. History of miscarriage or preterm delivery.

16. Management of hypothyroidism in
Pregnancy
• Thyroxine dose require increment at 4-6
weeks of pregnancy and gradually increase up
to 20 weeks then plateau until time of
delivery.
• Those having thyroidectomy or radioablation
require more increase in dose than
autoimmune thyroid disease.
• Subclinical hypothyroidism needs be treated

17. Euthyroid women, (+) TPO
Ab's
• Euthyroid pregnant women with (+) TPO Ab's
develop impaired thyroid function as pregnancy
proceeds
• Treatment with Thyroxin reduces the risk of
miscarriage and prematurity in TPO Ab (+)
women

18. Euthyroid women, (+) TPO
Ab's
Miscarriege – 2-5 fold
• 70. Stagnaro-Green A, Roman SH, Cobin RH, el-
Harazy E, AlvarezMarfany M, Davies TF 1990
Detection of at-risk pregnancy by means of highly
sensitive assays for thyroid autoantibodies.
JAMA264:1422–1425

19. Euthyroid women, (+) TPO
Ab's
Peinatal death ATA 2017
Yes -191,
No death- 140 196
RDS
Yes -197
Intellectual Motor development 25-30 month -199
Neurocognition -5.5 yrs -200
Sensory neural loss @ 8 yrs -141
Low IQ @ 4 yr normal at 7 yrs --201
Autism spectrum-203

20. Increased Thyroxine requirement
during pregnancy
Known Hypothyroidism already on
LT4
• ↑ dose by 30% taking extra pill 2 days a
week as soon as pregnancy is confirmed.
• To make further dose changes based on
serum FT4 + TSH levels

21. • Thyroxine ingestion should be separated from
prenatal vitamins containing iron, iron and calcium
supplements, and soy products by at least 4 hours to
ensure adequate absorption.
• After delivery, reduce thyroxin to pre pregnancy
dosage, and check serum TSH in 6 weeks

22. Management contd..
Factors responsible for need of more
thyroxine during pregnancy
• ↑ in TBG (2- to 3-fold) due to E2
•↑ renal LT4 clearance
• Transfer of LT4 to the fetus
• Increased placental deiodinase activity
• Reduced Gl absorption due to iron
supplementation.

24. • Pregnancy has a profound impact on thyroid
function.
• Trimester specific TSH range should be followed
to diagnose hypothyroidism and thyroxine dose
adjustment.
• SCH and antibody positivity are important issue in
treating hypothyroidism in pregnancy.
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