Pregnancy Flashcards
what can hypo and hyperthyroidism lead to?
anovulatory cycles- reduced fertility
why is maternal thyroxine important for neonatal development?
CNS development
what can the increased demand of thyroxine in pregnancy lead to?
enlarged thyroid gland
what is unable to compensate for the increased demand of thyroxine during pregnancy?
pre-existing hypothyroidism
hypothyroidism management in pregnancy
increase thyroxine dose by 25mcg as soon as pregnancy expected
check TFTs monthly for first 20 weeks then every 2 months until term
average dose increase of levothyroxine in pregnancy
increases by 50%, aim for TSH <3mU/l
risks of untreated hypothyroidism in pregnancy
increased abortion pre-eclampsia abruption postpartum haemorrhage preterm labour foetal neurophysiological development (average IQ 7 points lead and increased risk of IQ below 85)
what does hCG do?
increases thyroxine which suppresses TSH
what is hCG a similar structure to?
TSH
both have two peptide chains with an identical chain
abnormal thyroid function tests in pregnancy
hCG effect (TSH-like effect): T4 increased, low TSH (mimics hyperthyroidism)
what does the hCG effect cause?
hyperemesis gravidarum
what distinguishes hyperemesis from hyperthyroidism (gestational hCG-associated thyrotoxicosis)
hyperemesis gravidarum= high hCG and low TSH
not TRAb antibody positive
resolves by 20 weeks gestation
only treat if persists beyond 20 weeks
complications in pregnancy for hyperthyroidism
infertility/amenorrhoea spontaneous miscarriage still birth thyroid crisis in labour transient neonatal thyrotoxicosis
causes of thyrotoxicosis in pregnancy
Grave’s
TMNG, toxic adenoma
thyroiditis
hyperthyroidism management in pregnancy
- wait and see (maybe hyperemesis)
- Grave’s may settle as pregnancy suppress AI
- beta blockers
- low dose ATD
why is hyperemesis difficult to distinguish from hyperthyroidism?
both present with nausea, vomiting, tachycardia, warm, sweaty and lack of weight gain
ATDs in pregnancy
PTU for first trimester then carbimazole for 2-3rd trimesters
adverse of carbimazole
embryopathy in 1st trimester
adverse of PTU
liver toxicity (best avoided except first trimester)
when should TRAb antibodies be checked in pregnancy?
third trimester
why should you check TRAb antibodies?
if present alert neonatologist
TRAb can cross placenta and cause neonatal transient hyperthyroidism
what is there an increased risk after pregnancy of in T1DM?
post-partum thyroiditis
what can the transient thyrotoxic state cause after pregnancy?
hypothyroidism which can persist for up to 1 year
presentation of hypothyroidism
small diffuse non-tender goitre
hypothyroid phase is associated with postnatal depression
postpartum exacerbation of all AI
