Thyroid

Question 1

what are adverse outcomes associated with thyroid disorders

Answer 1

• miscarriage, fetal loss
• gestational hypertension, pre-eclampsia
• intrauterine growth restriction [IUGR]
• compromised fetal neurocognitive development
• fetal distress
• stillbirth
• premature birth
• lactation difficulty
• postnatal depression
• thyroid storm
• maternal congestive heart failure

Question 2

normal production of thyroid hormones [T3 and T4] is dependent on

Answer 2

• an adequate supply of dietary iodine
• a normally functioning thyroid gland
• a functioning pituitary gland producing adequate TSH
• a functioning hypothalamus producing adequate TRH

Question 3

where is iodine found

Answer 3

in seafood, vegetables grown in iodine-rich soil, and iodized table salt.

Question 4

clinical picture of hyperthyroidism [high T3 and T4]

Answer 4

• increased basal metabolic rate
• weight loss with good appetite
• anxiety, physical restlessness, nervousness, excessively emotional
• hair loss
• fast pulse, heart palpitations
• intolerance to heat, warm sweaty skin
• diarrhea
• exophthalmos [protrusion of the eyes] in Graves’ disease
• oligomenorrhea or amenorrhea

Question 5

what is the clinical presentation of hypothyroidism [low T3 and T4]

Answer 5

• decreased basal metabolic rate
• weight gain and poor appetite. easily fatigues
• mental sluggishness, depression, lethargy, psychosis
• dry skin, brittle hair
• slow, weak pulse
• dry cold skin, poor tolerance to cold. puffy appearance on face hands and feet [myxedema]
• constipation
• anovulation

Question 6

what are some of the changes to maternal thyroid function in pregnancy

Answer 6

• a marked increase of TBG
• Increased T3 and T4
  fetal requirements for thyroid hormone in first trimester
• increased demand for iodine
• hCG has a thyroid- stimulating effect
• de-iodination of thyroid hormones in the placenta to facilitate passage of iodine to the fetus
• thyroid function tests are difficult to interpret

Question 7

What thyroid hormone crosses the placenta

Answer 7

iodine crosses the placenta and thyroxine [T4] is transferred, but only in the 1st trimester. T3 and TSH do not cross at all

Question 8

when does the fetal thyroid begin functioning

Answer 8

at the end of the 1st trimester, and prior to that the fetal brain development is dependent on maternal supply of T4, which is converted intracellularly to T3. during this time thyroid hormones are most important to fetal brain development.

Question 9

what is fetal intellectual development dependent on

Answer 9

adequate amounts of thyroid hormone. Deficiencies can lead to impaired growth and irreversible intellectual disability.

Question 10

what happens in women with severe iodine deficiency during pregnancy

Answer 10

trapping mechanisms override fetal demand, conserving iodine for maternal use but this results in congenital iodine deficiency syndrome [poor growth and intellectual deficiency ]

Question 11

why might hCG cause transient biochemical hyperthyroidism

Answer 11

hCG and TSH share a similar structure and have similar receptors, giving hCG thyroid-stimulating features. hCG stimulates the thyroid gland during early pg. In situations with high hCG like multi-fetal pg, molar pg, and HG hCG may overstimulate the TSH receptors causing the transient hyperthyroidism

Question 12

what is the thyroid activity in labor and birth

Answer 12

the levels of total and free T3 increase in response to the increase energy requirement of the contracting uterine muscles.

Question 13

what happens to the thyroid during pp

Answer 13

delivery of placenta and consequent reduction in estrogen, the production of TBG decreases, as does the renal excretion of iodine. gradually over 4-6 weeks the changes to thyroid function of pg are reversed.

Question 14

when is the diagnosis of thyroid disorders ideal

Answer 14

pre-conception as some diagnostic tools and treatments are inadvisable in pg

Question 15

how can hyperthyroidism affect pregnancy

Answer 15

lead to hypertensive disease of pg, cardiac disease, infection, IUGR, stillbirth, abruption or preterm labor, and thyroid storms

Question 16

what is a thyroid storm

Answer 16

or thyrotoxin crisis is a rare but acute and life threatening event. presents with variety of serious symptoms- pyrexia, agitation, confusion, tachycardia [and fetal tachycardia], and congestive heart failure. predisposing factors labor and delivery and infections/ trauma in those with less well controlled

Question 17

what if hyperthyroidism present first during pregnancy

Answer 17

thyrotoxicosis usually occurs in late first or early second trimester and can be hard to diagnose because many of s/s are common during pg

Question 18

what is the typical care/ treatment for those with hyperthyroidism during pg

Answer 18

regular blood tests to assess thyroid function in pg [and probably an increased number for those newly diagnosed]. about 30 percent of women can discontinue their medications towards the end of pg as the immune suppressive effect of pg leads to reduced antibody levels

Question 19

what increased risk is there with the fetus [hyperthyroidism]

Answer 19

risk of fetal thyrotoxicosis, may be suspected during antepartum with persistent fetal tachycardia [170] and confirmed on u/s [fetal goiter with or without IUGR]. if suspected needs carful higher monitoring as an increased fetal mortality rate has been identified as wel as other complications.

Question 20

what to consider pp with hyperthyroidism

Answer 20

• cord blood should be taken at delivery to test neonatal thyroid function, and pediatrician should be informed.
• abnormal maternal thyroid hormone levels can impact milk letdown and can affect breastfeeding

Question 21

what is the main cause of hypothyroidism worldwide

Answer 21

iodine deficiency

Question 22

iodine deficiency is the most common cause of what

Answer 22

preventable intellectual and developmental disability known as congenital iodine deficiency syndrome

Question 23

what is them most common cause of hypothyroidism in developed countries

Answer 23

result of autoimmune destruction of thyroid tissue. Atrophic autoimmune thyroiditis and Hashimoto’s thyroiditis [chronic autoimmune thyroiditis ]

Question 24

What are some risks with hypothyroidism

Answer 24

miscarriage, pre-eclampsia, abruption, low birth weight, stillbirth, and preterm birth, and increased rates of gestational hypertension and rarely myxedema coma

Question 25

what to keep in mind in pp with hypothyroidism

Answer 25

may predispose to postnatal depression

Question 26

what is postpartum thyroiditis

Answer 26

an inflammatory autoimmune disorder. onset usually is usually within the first few months postnatal. most women progress through hyperthyroidism and hypothyroidism, then symptoms spontaneously resolve usually within 12 months. symptoms may include depression and memory impairment, together with ‘classical’ symptoms such as heat/cold intolerance, fatigue and palpitations