Chronic conditions in pregnancy

Question 1

What are common chronic conditions in pregnancy that need additional management?

Answer 1

• hypothyroidsm
• hypertension
• epilepsy
• RA

Question 2

What can under-treated or untreated hypothyroidism in pregnancy lead to?

Answer 2

• miscarriage
• anaemia
• small for gestational age
• pre-eclampsia.

Question 3

A 28 year old G2P1 is 7 weeks into her pregnancy. She has a history of hypothyroidism for which she is taking 50 micrograms of levothyroxine daily. She reports feeling well in herself and no symptoms. Thyroid function tests are performed and the results indicate the following:

Free thyroxine (fT4) 18 pmol/l (11-22 pmol/l)

Thyroid-stimulating hormone (TSH) 2.1 μu/l (0.17-3.2 μu/l)

Which of the following is the next best step in the management of this patient?

A. Make no changes and continue the same dose of levothyroxine as the patient’s test results are within normal ranges

B. Increase levoythyroxine by 25 mcg and repeat the thyroid function tests in 4 weeks

C. Reduce levothyroxine by 25 mcg as there is a physiological increase in fT4 in early pregnancy

D. Thyroid function tests should be repeated in third trimester

E. Increase levothyroxine by 25 mg and repeat tests in 2 weeks

Answer 3

B. Increase levoythyroxine by 25 mcg and repeat the thyroid function tests in 4 weeks

NICE recommends increasing levothyroxine by 25 mcg as soon as pregnancy is confirmed despite a euthyroid state. This patient is currently euthyroid but because of her pregnancy, needs an increased dose of levothyroxine. The explanation for this is that in pregnancy there is a physiological increase in serum free thyroxine until the 12th week of pregnancy as the foetus is dependent on mother’s circulating thyroxine until the 12th week of development when the foetal thyroid develops. Untreated hypothyroidism can lead to neurodevelopmental delay of the foetus. This surge is not seen in hypothyroid patients. Therefore, levothyroxine should be increased to mimic this surge

Question 4

What is hypothyroidism treated with in pregnancy?

Answer 4

• levothyroxine(T4)
• an cross the placenta and provide thyroid hormone to the developing fetus
• levothyroxine dose needs to be increased during pregnancy, usually by at least 25 – 50 mcg
• Treatment is titrated based on the TSH level, aiming for a low-normal TSH leve

Question 5

What changes to medication for women with hypertension during pregnancy need to be made?

Answer 5

Medications that should be stopped:

• ACE inhibitors (e.g. ramipril)
• Angiotensin receptor blockers (e.g. losartan)
• Thiazide and thiazide-like diuretics (e.g. indapamide)

Question 6

What hypertensive medications are not known to be harmful during pregnancy?

Answer 6

• Labetalol (a beta-blocker – although other beta-blockers may have adverse effects)
• Calcium channel blockers (e.g. nifedipine)
• Alpha-blockers (e.g. doxazosin)

Question 7

What affect might pregnancy have on pts with epilepsy?

Answer 7

• may worsen seizure control due to the additional stress, lack of sleep, hormonal changes and altered medication regimes
• Seizures are not known to be harmful to the pregnancy, other than the risk of physical injury
• Ideally, epilepsy should be controlled with a single anti-epileptic drug before becoming pregnant.

Question 8

What epileptic medications are safe and which are harmful during pregnancy?

Answer 8

• Levetiracetam, lamotrigine and carbamazepine are the safer anti-epileptic medication in pregnancy
• Sodium valproate is avoided as it causes neural tube defects and developmental delay
• Phenytoin is avoided as it causes cleft lip and palate

Question 9

How does pregnancy affect pts with RA?

Answer 9

• Ideally, RA should be well controlled for at least three months before becoming pregnant
• Often the symptoms of RA will improve during pregnancy and may flare
• treatment may need to be altered before and during pregnancy

Question 10

What RA medications are safe and which are harmful during pregnancy?

Answer 10

• Methotrexate is contraindicated, and is teratogenic, causing miscarriage and congenital abnormalities
• Hydroxychloroquine is considered safe during pregnancy and is often the first-line choice
• Sulfasalazine is considered safe during pregnancy
• Corticosteroids may be used during flare-ups

Question 11

What are some general medications that are avoided during pregnancy?

Answer 11

• NSAIDs
• Beta-blockers except for labetalol
• ACEi and ARBs
• Opiates
• Warfarin
• Sodium valporate
• Lithium
• SSRIs
• Isotretinoin (Roaccutane) (vit A)

Question 12

What VTE drugs are contraindicated in pregnancy?

Answer 12

Novel oral anticoagulants (eg rivaroxaban) & warfarin are contraindicated for use in pregnancy and therefore women already on NOACs should be changed over to low molecular weight heparin

Question 13

what are risk factors for VTE in pregnancy?

Answer 13

-Age > 35
-Body mass index > 30
-Parity > 3
-Smoker
-Gross varicose veins
-Current pre-eclampsia
-Immobility
-Family history of unprovoked VTE
-Low risk thrombophilia
-Multiple pregnancy
-IVF pregnancy

Question 14

what happens if a pregnant women has 4 or more Rfs for VTE?

Answer 14

Four or more risk factors warrants immediate treatment with low molecular weight heparin continued until six weeks postnatal.

If diagnosis of DVT is made shortly before delivery.

Question 15

what happens if a pregnant women has 3 or more Rfs for VTE?

Answer 15

If a woman has three risk factors low molecular weight heparin should be initiated from 28 weeks and continued until six weeks postnatal.

Question 16

what happens if diagnosis of VTE shortly before delivery?

Answer 16

continue anticoagulation treatment for at least 3 month, as in other patients with provoked DVTs

Question 17

what is the most common cause of thyrotoxicosis in pregnancy?

Answer 17

Graves’ disease is the most common cause of thyrotoxicosis in pregnancy.

It is also recognised that activation of the TSH receptor by HCG may also occur - often termed transient gestational hyperthyroidism. HCG levels will fall in the second and third trimester

Question 18

management of hyperthyroidisim in pregnancy:

Answer 18

1. propylthiouracil has traditionally been the antithyroid drug of choice
   -however, propylthiouracil is associated with an increased risk of severe hepatic injury

-therefore NICE Clinical Knowledge Summaries advocate the following: ‘Propylthiouracil is used in the first trimester of pregnancy in place of carbimazole, as the latter drug may be associated with an increased risk of congenital abnormalities.

-At the beginning of the second trimester, the woman should be switched back to carbimazole’

-maternal free thyroxine levels should be kept in the upper third of the normal reference range to avoid fetal hypothyroidism

-thyrotrophin receptor stimulating antibodies should be checked at 30-36 weeks gestation - helps to determine the risk of neonatal thyroid problems

-block-and-replace regimes should not be used in pregnancy

-radioiodine therapy is contraindicated

Question 19

how are women monitored after thyroxine use in pregnancy:

Answer 19

1. thyroxine is safe during pregnancy
2. serum thyroid-stimulating hormone measured in each trimester and 6-8 weeks post-partum
3. women require an increased dose of thyroxine during pregnancy
   by up to 50% as early as 4-6 weeks of pregnancy
4. breastfeeding is safe whilst on thyroxine

Question 20

what are the stages of postpartum thyroiditis:

Answer 20

1. Thyrotoxicosis
2. Hypothyroidism
3. Normal thyroid function (but high recurrence rate in future pregnancies)

Question 21

investigation for postpartum thyroiditis:

Answer 21

Thyroid peroxidase antibodies are found in 90% of patients

Question 22

management of postpartum thyroiditis:

Answer 22

1. thyrotoxic phase
   -propranolol is typically used for symptom control
   not usually treated with anti-thyroid drugs as the thyroid is not overactive.
2. hypothyroid phase
   -usually treated with thyroxine

Question 23

management of postpartum thyroiditis:

Answer 23

1. thyrotoxic phase
   -propranolol is typically used for symptom control
   not usually treated with anti-thyroid drugs as the thyroid is not overactive.
2. hypothyroid phase
   -usually treated with thyroxine