Diabetes and Endocrinology in Pregnancy Flashcards
Key events in the ovarian cycle?
Day 1 is when menstruation begins
- Follicular growth occurs at day 10 and oestradiol is produced
- Ovulation occurs at day 14 and LH secretion peaks
- Luteal function begins and the follicle develops the corpus luteum; progesterone and oestradiol are produced
Hormone produced during progression from follicle to progesterone?
Follicle - oestradiol
Implanted fertilised ovum - HCG (pregnancy test basis)
Corpus luteum - progesterone
Hormones produced by the placenta?
Human Placental Lactogen (hPL)
Placental progesterone
Placental oestrogens
Hormones produced by the pituitary, in relation to pregnancy?
Prolactin (lactogen)
Development of gestational diabetes?
Progesterone and hPL produced during pregnancy cause insulin resistance in the mother
In a predisposed individual, the BG rises and gestational diabetes occurs
3 types of diabetes in pregnancy?
- T1DM
- T2DM
- Gestational diabetes mellitus (tends to occur in the 3rd trimester)
When does foetal organogenesis begin?
5 weeks and possibly earlier
Complications of diabetes in pregnancy?
Congenital malformation
Prematurity
Intra-uterine growth retardation (IUGR) - small baby
Macrosomia - large baby
Polyhydramnios (excessive amniotic fluid)
Intrauterine death
Complications of diabetes in pregnancy for the neonate?
Respiratory distress due to immature lungs
Hypoglycaemia causes fits, which may cause brain damage
Hypocalcaemia causes fits, which may cause brain damage
CNS defects that can occur due to diabetes in pregnancy?
Anencephaly (absence of a major portion of the brain, skull, and scalp that occurs during embryonic development)
Spina bifida
Skeletal abnormalities that can occur due to diabetes in pregnancy?
Caudal regression syndrome
Genital and GI abnormalities that can occur due to diabetes in pregnancy?
Ureteric duplication
How does macrosomia occur?
Maternal hyperglycaemia causes foetal hyperglycaemic and hyperinsulinaemia
In the 3rd trimester, the foetus produced its own insulin (a major growth factor) but, in addition to the extra insulin, this causes macrosomia and neonatal hypoglycaemia
Pre-pregnancy counselling for T1DM or T2DM patients?
Good BG control pre-conception limits the risk of congenital malformation
Management of a pregnancy in T1DM and T2DM?
Folic acid (5mg); in a non-diabetic patient, the dose is only 400mcg
Consider a change from oral medication to insulin
Regular eye checks are required (3 monthly) due to accelerated retinopathy
How should BP be managed in pregnancy?
Avoid ACEIs and statins
For BP control, use:
• Labetalol
• Nifedipine
• Methyldopa
Management of pregnancy for all (T1DM, T2DM and GDM)?
Follow a diabetic diet and aim for BG control:
• Pre-meal: <4 - 5.5 mmol/L
• 2 hours post-meal: <7 mmol/L
Monitor HbA1c and BP
Maintain BG during labour with IV insulin and IV dextrose
Pharmacological treatment of GDM?
- Lifestyle Mx
2. Metformin; they may need insulin
Follow-up of GDM?
A glucose tolerance test is done 6 weeks post-natal to ensure resolution of DM
If it has not resolved, they have T2DM
Implications of GDM?
A marker of insulin resistance
With GDM, 50% go on to develop T2DM within 10-15 years; this is even higher for obese patients
Some patients, e.g: if they are thin, may actually have T1DM
Methods of preventing diabetes following GDM?
Keeping weight as low as possible with aerobic exercise and a healthy diet: • Low refined sugar • Predominant sugar • Low saturated fat • Low energy foods
Metformin, acarbose, etc, can be considered
Annual fasting glucose must be checked
Thyroid demand during pregnancy?
Increased demand during pregnancy and maternal thyroxine is important for neonatal development in early pregnancy, esp. of the brain
Thyroid gland increases in size and there is increased T4 production, to maintain normal conc.
What is anovulatory cycle?
Menstrual cycle during which the ovaries do not release an oocyte; thus, ovulation does not occur
Hype and hyperthyroidism can cause this
Effect of pregnancy on thyroid hormones?
Plasma protein binding increases
Effect of hCG in pregnancy?
Free T4 (fT4) increases in some pregnancies
Low TSH in some pregnancies
Hyperemesis gravidarum can occur
What is hyperemesis gravidarum?
Severe nausea and vomiting during pregnancy, such that weight loss and dehydration occur
Biochemistry in hyperemesis gravidarum?
hCG high
Majority have abnormal TSH/fT4
Action of TSH and hCG?
TSH and hCG both increase thyroxine, which suppresses TSH
Structural similarities and differences between TSH and hCG?
Both are 2 chain peptides in which the:
• α-chain is identical
• β-chain is different
How to manage pre-existing hypothyroidism in pregnancy?
INCREASE thyroxine dose by 25mcg AS SOON AS pregnancy is suspected (do not wait for blood tests)
Check TFTs monthly for the 1st 20 weeks and then every 2 months until term
TSH aim in pregnancy?
<3 mU/L
Risk of untreated hypothyroisidm in pregnancy?
Foetal neuropsychological development, e.g: lower IQ
Increased risk of: • Abortion • Pre-eclampsia • Abruption • Post-partum haemorrhage • Pre-term labour
Risk of hyperthyroidism?
Infertility
Spontaneous miscarriage
Stillbirth
Thyroid crisis (AKA storm) in labour
Transient neonatal thyrotoxicosis (a jittery baby that does not feed properly or put on weight)
Causes of thyrotoxicosis in pregnancy?
- Grave’s disease
- Toxic multi-nodular goitre (TMNG), toxic adenoma
- Thyroiditis
How to distinguish hyperemesis from hyperthyroidism?
Hyperemesis has:
• Increased hCG and decreased TSH
• Not TRab antibody +ve
• IMPROVES/resolved by 20 weeks gestation (on the other hand, hyperthyroidism worsen as time progresses)
Treatment of thyrotoxicosis in pregnancy?
ONLY treat if it persists >20 weeks (supportive Mx in this time); if it settles, it was hyperemesis. Also, Grave’s may settle as pregnancy suppresses autoimmunity
β-blockers, if required
LOW DOSE anti-thyroid drugs:
• 1st trimester - propylthiouracil
• 2/3rd trimester - Carbimazole
….WAIT AS LATE AS POSSIBLE BEFORE STARTING THESE
Problems with carbimazole in pregnancy?
Can cause: • Embryopathy in 1st trimeter • Scalp abnormalities • GI abnormalities • Choanal & oesophageal atresia
Problems with propylthiouracil in pregnancy?
Risk of liver toxicity
Best to avoid, except possibly in the 1st trimester and then switch to carbimazole
TRAb antibodies in pregnancy?
Check these in the 3rd trimester and, if present, suspect thyroid dysfunction in the fetus
These antibodies can cross the placenta and cause NEONATAL TRANSIENT HYPERTHYROIDISM
Describe post-partum thyroiditis
Tends to occur ~6-8 weeks following labour
At 4-6 months, female develops hypothyroidism, so she is not treated before this
Should recover ~12 months post-partum, although some develop persistent hypothyroidism, i.e: beyond 1 year
Presentation of post-partum thyroiditis?
Small, diffuse, non-tender goitre
What is the thyroid status of the pregnancy woman at 10 weeks gestation: • fT4 15 (10-20) • TT3 3.4 (up to 2.6) • TSH 0.3 (0.4-4) ?
hCG-mediated suppression of TSH is most likely (this is normal)
However, it could also be early Grave’s disease
