Thyroid Flashcards
In normal pregnancy thyroid hormone production typically:
Increased by 30-50%
TSH in pregnancy
Low, rises to almost normal in second trimester
Iodine supplementation in pregnancy
Increased demand for thyroid hormone (50%)
-thyotropic regulation by hcg
-oestrogen mediated thyroxine binding globulin increase
Increased renal iodine clearance (30-50%)
Iodide transferred to the fetus (50-75mcg/day)
Fetal brain damage iodine deficiency
Cretinism
Subclinical hypothyroidism and goiter
Intellectual deficit/loss of iq
ADHD
Overt maternal hypothyroidism
TSH>2.5 with a decreased FT4 concentration OR TSH>10
Subclinical hypothyroidism
Serum TSH between 2.5 and 10 with a normal FT4 concentration
Adverse maternal effects of overt hypothyroidism
Higher rate miscarriage (2x)
Gestational HTN
Prem labour
Adverse fetal effects with maternal hypothyroidism
Increased infant morbidity and mortality
Low bw
Decreased IQ
Cretinism
Pre-existing hypothyroidism thyroxine dose
Adjust dose to reach and maintain a TSH<2.5
Thyroxine dose should increase by 25-30% on confirmation of pregnancy
Hypothyroidism first recognized in pregnancy thyroxine dosing
TSH 2.5-10: thyroxine 50mcg day
TSH> 10:thyroxine 75-100mcg day
Normal range for TSH in first trimester of pregnancy
0.1-2.5
Postpartum thyroid it is
Transient thyrotoxicosis and or hypothyroidism
50% need ongoing thyroxine
TRAb
Can cross placenta and lead to neonatal graves
Recheck titre at 30-23 weeks
Specific for graves
Risk factors for thyroid disease
Age >35 Infertility Recurrent miscarriage Previous pre-term birth Previous irradiation to head and neck
Pp thyroiditis
Abnormal TSH
Absent trab
No toxic nodule
Treat w beta blockers NOT thyroid meds if hyperthyroid
Thyroxine if hypothyroid
