Endocrine disease in pregnancy

1. Endocrine disease in pregnancy
SpR teaching
6/5/16

2. (ambitious) Objectives:
• Hypothyroidism:
– treatment, monitoring, outcomes
• Hyperthyroidism:
– prenatal counselling, treatment options,
complications, monitoring
• Prolactinoma
• Addison's

3. Case 1
30 yr old woman, 1st pregnancy, 8/40
Diagnosed with Hashimotos 5 yrs ago, on
levothyroxine 125 mcg OD
Last TSH 3.4 6/12 ago
GP calls for advice: what do you recommend?

4. Hypothyroidism discussion points:
• What are the risks of under-treated hypothyroidism?
– Both obstetric and to offspring
• What is the “right” TSH target?
• Would you change her T4 dose?
• How often to monitor TFTs?
• (Should we screen for hypothyroidism in pregnancy?)

5. Hypothyroidism
• TSH Ref range in pregnancy is lower:
– ideally use trimester/assay specific range, typically:
– TSH <2.5 during 1st trimester
– TSH <3 2nd/3rd trimester
• Dose: 1.5-2mcg/kg /day…. or increase daily
dose by 30-50% .... or take 2 extra doses per
week. Ideally optimise pre-pregnancy.

6. Risks of under-treated hypothyroidism
• Miscarriage
• Abruption
• Prematurity
• Pre-eclampsia
• Adverse neurodevelopmental outcomes in
offspring
– Haddow et al, NEJM 1999
– Li et al, Clin Endo 2010 …….and lots more

7. Case 2
22 yr old woman with T1DM
Unplanned pregnancy, now 6/40
• TSH 4.1, fT4 13 (and HbA1c 85…)
• Would you start levothyroxine?
• What dose?
• What about post natal treatment?

8. Subclinical hypothyroidism
• To screen or not to screen?
• To treat or not?
– Does it make a difference if TPO+ve or not?
• Should treatment be continued postnatally?

9. Case 3
• 36 yr old woman
• 3rd pregnancy, now 11/40
• Seen by OBS with hyperemesis, admitted for
treatment
• TSH 0.016, fT4 26

10. Thyrotoxicosis in pregnancy
• What’s the underlying aetiology?
– Goitre, TED, TRAB, fT3?
• Natural history of GTT?
• Treatment?

11. Case 4
40 yr old woman, 4th pregnancy (unplanned)
Referred by community midwife at 14/40.
Previously seen in endocrine clinic with Graves
disease. Variable concordance treatment.
No medication at present.
fT4 29, fT3 9, TSH <0.014

12. Pre-existing hyperthyroidism and
pregnancy
• Pre-pregnancy advice
• Medication choices
• Monitoring

13. Complications of untreated Graves
disease in pregnancy
• Foetal:
– Miscarriage
– IUGR
– Prematurity
– Placental abruption
– Neonatal thyrotoxicosis
• Maternal:
– Preeclampsia
– Thyroid storm
– High output cardiac failure

14. Treatment options in pregnancy
• ATDs: PTU v CBZ
– Both equally effective, & both cross placenta
– Carbimazole embryopathy v PTU hepatotoxicity (&
?? Birth defects)
– PTU 1st trimester then switch to CBZ
– Keep fT4 to upper end of ref range
– Do not use block & replace
– Short term b blocker use is fine
• Surgery: only in difficult cases; 2nd trimester
• RAI: absolutely contraindicated

16. Graves disease in pregnancy: monitoring
• TFTs 3-4 wkly after each dose change, 6-8 weekly if
stable
• Check TRAB at 24-28/40: if +ve, foetal USS monthly for
foetal goitre from 28/40
• Aim for lowest possible ATD dose; may be able to stop
medication by 3rd trimester.
• Target fT4 towards upper end of ref range
• Risk of relapse post partum
• low dose ATDs fine if breastfeeding (even though
excreted into and found in breast milk: take in divided
doses post feed)

17. Foetal hyperthyroidism
• High foetal heart rate (>160 beats/minute)
• foetal goitre
• poor growth
• craniosynostosis
• Cardiac failure and hydrops may occur with
severe disease.

18. Case 5
• 33 yr old woman
• Presented with primary infertility
• PRL 1800 – 2500, no medication
• MRI: 11mm prolactinoma
• Started on cabergoline 500mcg weekly
• PRL into normal range; wants to conceive ASAP.
• Asks about pregnancy management: what do you tell
her?

19. Prolactinoma and pregnancy
• Micro v. macro
• Treatment in pregnancy
• Monitoring
• Postnatal management

20. Case 6
• 28 yr old woman
• Seen at 11/40 with presyncope, nausea &
vomiting: treated symptomatically (BP 80/40,
Na 129)
• Low BP noted at CMW appointments
• Presents at 28/40 with prem labour and IUGR
• Profound hypotension post delivery. Na 122
• SST: baseline cortisol 34, rises to 44!

21. Addison’s and pregnancy
• No XS foetal morbidity (if pre-existing Addison’s)
• Management no different to non-pregnant state
• May need HC dose increase 3rd trimester (or times of
acute stress) > extra 5-10mg daily
• Fludrocortisone: no change
• In labour: HC 50-100mg IM QDS, or 200mg/24hr via
continuous IVI
• Tail off back to normal dose post delivery/for
breastfeeding

22. Addison’s presenting in pregnancy
• May present as adrenal crisis at time of delivery
due to late diagnosis
• Associated with foetal growth restriction
• Diagnose in usual way
• No pregnancy specific ref range available for
cortisol/ACTH, but cortisol normally rises in
pregnancy so use higher cutoffs e.g random am
cortisol< 300 in 1st trimester, < 450 in 2nd
trimester, <600 in 3rd, should raise suspicion in
clinical context

23. What we haven’t talked about…
• Phaeochromocytoma
• Cushings
• Hypopituitarism
• Primary hyperparathyroidism
• CAH

24. Questions?