Thyroid Dysfunction And Reproductive Health Flashcards
What is the most common endocrine condition affecting women of reproductive age?
Thyroid dysfunction
What is recommended about thyroid measurements in subfertile women?
No routine measurements in asymptomatic patients
What is the rate of hyperthyroidism in subfertile women compared with general population?
2.3 % compared with 1.5 % in general population
What menstrual irregularity associated with hyperthyroidism?
Hypomenorrhoea
Polymenorrhoea
+ sensitivity to Gnrh 》+ Lh 》 + SHBG 》 + total estrogens
What is the rate of anovulatation in women with hyperthyroidism ?
Most women remain ovulatory.
And there is no evidence that treatment of either subclinical or clinical hyperthyroidism improves the rate of ovulation
What is the impact of radioactive iodine on fertility?
No deterioration in gonadal function
Or adverse outcomes in offspring
What is the period of time the pregnancy is delayed after treatment with radioactive iodine?
6 months
What drug causes hypothyroidism?
Amiodaron / lithium
What is the prevalence of hypothyroidism and subclinical hypothyroidism in women in reproductive age?
0.5 %
Subclinical: 2 - 4 %
How does hypothyroidism affect fertility?
It affects the pulsatile release of GnRH which is required for cyclical release of fsh Lh
What TSH level is required in women undergoing ART?
< 2.5 mu/ml
The impact of treatment with levothyroxine( in women with overt or subclinical hypothyroidism) on implantation and pregnancy and live birth rates?
Improves the rates . But still reduced compared with euthyroid
Recommendations about TSH levels in sub fertility setting ?
Keep tsh below 2.5 mu/ml per conception in line with guidelines for first trimester tsh levels
What is the most common cause for hypothyroidism in women of reproductive age?
Autoimmune thyroid disease
AITD
Thyroid autoantibodies are present in what rate in :
Hashimoto’s thyroiditis
Postpartum thyroiditis
Graves disease
All
2/3
3/4
Respectively
What is the prevalence of thyroid autoimmunity among general population?
Up to 25%
And higher in those with endometriosis and pco
And subfertile group
Management of thyroid diseases in the fertility setting if Tsh 2.5 - 4.5 ?
1 - repeat Tsh
2- test thyroid autoantibodies
If tsh still > 2.5 commence thyroxin.
And test tsh every 6 weeks until < 2.5
If +ve antibodies in case of pregnancy results : monitor TFT
Fetal growth
Management of thyroid diseases in fertility setting if TSH > 4.5 ?
1- commence levothyroxine
2- check T3 T4 autoantibodies
What are the physiological changes of pregnancy in thyroid functions ?
- 1- increased thyroid binding globulin due to estrogen stimulation
2- increased clearance if free thyroid hormones due to increased glomerular filtration
Result in : reduction in free thyroid hormones - bhcg is closely related structurally to Tsh which stimulates thyroid hormones release and suppresses Tsh in first trimester
- in 2nd and 3d trimester Bhcg levels fall accompanied by rise in tsh
What is the miscarriage rate in women euthyroid and positive for thyroid autoantibodies ?
Three fold increase
What is the most common cause for hyperthyroidism in pregnancy?
Graves disease affecting 1 % of pregnancies
What is the cause of gestational hypothyroidism? Prevalence?
Stimulation of Tsh receptors by B hcg
Affecting 1-3% of pregnancies
How to distinguish between graves disease and gestational hyperthyroidism?
TSH stimulating receptors antibodies is diagnostic of graves disease TSI
Management of gestational hyperthyroidism?
Supportive management
(Free T4 tends to return to normal in 2nd trimester )
Thyroid replacement is not required
Management of Graves disease in pregnancy?
Propylthiouracil is preferred
( because of lower levels of teratogenicity
Carbimazol : in 2nd trimester
( concerns over propylthiouracil hepatotoxicity in offspring)
What are the risks of Graves disease in pregnancy?
Preterm birth
Pre eclampsia
FGR
Heart failure
Still birth
What is the particular risk in the infants of hypothyroidism mothers?
Neurodevelopmental delay
(Because of the fetal requirements for maternal T4 until 12 weeks of gestation ) after that T3 T4 Tsh don’t cross the placenta
What are the neonatal complications of hypothyroidism in pregnancy?
1- neurodevelopmental delay
2- neonatal hypothyroidism ( trans placental transfer of Tsh receptors blocking antibodies)(mainly seen in atrophic thyroiditis)
3- prematurity/ low birth weight
4- fetal distress in labour
5- stillbirth
6- perinatal death
7- congenial malformations
What are the maternal complications of hypothyroidism in pregnancy?
1- anaemia
2- postpartum hemorrhage
3- cardiac failure
4- pre eclampsia
5- placental abruption
What is the major risk in women euthyroid with AITD in pregnancy?
Preterm birth
2 to 4 folds Increased risk
(Eventhough treatment with thyroxin is not recommended )
What are the risk factors of thyroid dysfunction which indicates screening ?
1 History of thyroid dysfunction/surgery
2 Family history of thyroid dysfunction
3 Goitre
4 Clinical signs of hypothyroidism
5 + ve thyroid autoantibodies
6 Diabetes type 1
7 Other autoimmune disorders
8 History of miscarriage/preterm
9 History of subfertility
10 Age > 30
11 History of head/ neck irradiation
12 Previous treatment of amiodaron/lithium
13Recent exposure to iodine radiological agents
How to adjust L T4 dose in pregnancy?
Initially 25 mcg / daily
Tsh every 4- 6 weeks
Further increase may required to maintain the Tsh 0.5- 2.5
Trimester specific Tsh ranges ?
1st : 0.1 - 2.5
2nd : 0.2 - 3
3d: 0.3 - 3
How often Tsh would be tested in women euthyroid with AITD In pregnancy?
Every 4 weeks in early pregnancy
And at least once between 26-32 weeks
When to check Tsh postpartum in hypothyroidism women?
6-8 weeks postpartum
Is there any recommendations about euthyroid + AITD and treatment with LT4?
No recommendations of treatment both preconception or during pregnancy
