Endocrinology and Pregnancy Flashcards
What are the key events of the ovarian cycle?
Follicular growth = days 1-12, oestradiol produced
Ovulation = day 14
Luteal function = days 16-20, progesterone produced
What produced prolactin (lactogen)?
The pituitary
When does LH levels peak?
During ovulation
What contributes to insulin resistance in a mother?
Progesterone and hPL = if mother predisposed then blood glucose rises causing gestational diabetes
When does foetal organogenesis begin?
At 5 weeks (possibly earlier)
What are some complications in pregnancy caused by diabetes?
Congenital malformations, prematurity, macrosomia (>90th centile for size), intra-uterine growth retardation (IUGR), polyhydramnios, intrauterine death
What are some congenital malformations linked to diabetes?
Spina bifida, anencephaly, caudal regression syndrome, uteric dysfunction
What are some complications in neonates linked to diabetes?
Respiratory distress (immature lungs), fits due to hypoglycaemia or hypocalcaemia
Does diabetes increase the risk of congenital malformations?
Yes = CNS defects by 5x, skeletal defects by 200x, GI/GU defects by 20x
What causes macrosomia (BW >4kg) and neonatal hypoglycaemia?
Foetal hyperglycaemia and hyperinsulinaemia = caused by maternal hyperglycaemia, in 3rd trimester foetus produces own insulin which is major growth factor
How is the risk of congenital malformations reduced in patients with type 1 and 2 diabetes?
Pre-pregnancy counselling and good sugar control pre-conception
Why do type 1 and 2 diabetics get regular eye checks during pregnancy?
Their risk of retinopathy is accelerated
What medications should be avoided in type 1 and 2 diabetics during pregnancy?
ACE inhibitors, statins, labetol, nifedipine, methyldopa
What should type 1 and 2 diabetics be prescribed during pregnancy?
Folic acid 5mg (not 400ug as in non-diabetic pregnancy)
Consider change from tablets to insulin
Start aspirin 150mg at 12 weeks (in high risk pregnancy)
What is the management for all types of diabetes during pregnancy?
Diabetic diet and monitor HbA1c and blood pressure
Maintain good blood glucose during labour = IV insulin and IV dextrose
What is the blood sugar target during pregnancy for all kinds of diabetics?
Pre-meal = <4-5.5mmol/L
2hr post meal = <6.5-7mmol/L
What drugs are used during pregnancy to treat diabetes?
Type 1 = insulin
Type 2 = metformin, may need inulin later
Gestational = lifestyle, metformin, may need insulin
How is gestational diabetes confirmed?
6 week post natal fasting glucose or OGTT measured to ensure resolution = if not resolved then patient has type 2 diabetes
What is the risk of developing another form of diabetes 10-15 years following gestational diabetes?
<5% get type 1 diabetes
About 80% get type 2 diabetes
How can diabetes be prevented in patients who have had gestational diabetes?
Keep weight low as possible and healthy diet
Aerobic diet
Pioglitazone, acarbose, metformin (all possibilities)
Annual fasting glucose
How does thyroid disease reduce fertility?
Hypo/hyperthyroidism cause anovulatory cycles
How does thyroid disease impact pregnancy?
Maternal thyroxine important for neonatal development (especially CNS)
Increased demand on thyroid during pregnancy = increased T4 production
Plasma protein binding increases
What happens to patients already on thyroxine during pregnancy?
Develop relative thyroid deficiency = thyroid cant cope with increased demand
How should pre-existing hypothyroidism be managed during pregnancy?
Increase thyroxine dose by 25mcg as soon as pregnancy suspected, check TFT monthly for first 20 weeks then 2 monthly until term, aim for TSH <3mU/l
What are the risks of untreated hypothyroidism during pregnancy?
Increased abortion, pre-eclampsia, abruption, postpartum haemorrhage, pre-term labour, foetal neuropsychological development (increased risk of IQ <85)
What is the hCG effect on TFTs?
fT4 increased, low TSH (0.1-0.4), hyperemesis gravidarum (hCG high, 50% have low TSH)
How is hyperemesis different from hyperthyroidism?
Hyperemesis gravidarum = increased hCG, low TSH
Not TRab antibody positive
Resolves by 20 weeks gestation
only treat if persists 20 weeks
What does hyperemesis mimic biochemically?
Hyperthyroidism
What can hyperthyroidism during pregnancy cause?
Infertility/amenorrhoea (before conception), spontaneous miscarriage, stillbirth, thyroid crisis in labour, transient neonatal thyrotoxicosis
What can cause hyperthyroidism?
Grave’s disease (may settle as pregnancy supresses autoimmunity), TMNG, toxic adenoma, thyroiditis
What is the management of hyperthyroidism during pregnancy?
Beta blockers if needed, wait and see (will settle if hyperemesis), low dose antithyroid drugs (propylthiouracil in 2st trimester, carbimazole in 2nd/3rd trimester)
What are some features of carbimazole?
May cause embryopathy in first trimester (scalp and GI abnormalities, choanal and oesophageal atresia)
What are some features of propylthiouracil?
Risk of liver toxicity, best avoided except in first trimester (then switch)
Why should TRab antibodies be checked for during pregnancy?
Ideally checked in 3rd trimester = can cross placenta and cause neonatal transient hyperthyroidism
How common is postpartum thyroiditis?
5% of postpartum women, 25% of type 1 diabetics
What are some features of postpartum thyroiditis?
Transiently thyrotoxic, can last for up to 1 year postpartum, small diffuse non-tender goitre, hypothyroid phase associated with postnatal depression
How many patients develop persistent hypothyroidism following postpartum thyroiditis?
25-50%
