Master the board step 3

Master the Boards: USMLE Step 3
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Patients with a history of DVT or PE in a previous pregnancy or a history of
underlying thrombophilic condition should receive prophylactic LMWH
throughout pregnancy, unfractionated heparin during labor and delivery,
and warfarin for 6 weeks postpartum.
Thyroid Disorders
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Hyperthyroidism in pregnancy causes fetal growth restriction and stillbirth.
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Hypothyroidism in pregnancy causes intellectual deficits in offspring and
miscarriage.
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Pregnancy does not change the symptoms of hypothyroidism or hyperthyroidism
or the normal values and ranges of free serum thyroxine (T4) and
thyroid-stimulating hormone (TSH).
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Continue hormone replacement in patients with hypothyroidism during
pregnancy. Increase the dose by 25–30 percent when hypothyroid patients
become pregnant.
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Do not give thyroid replacement with triiodothyronine or desiccated thyroid.
The drug of choice is levothyroxine.
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Βeta blockers are the drug of choice for symptomatic hyperthyroidism.
Radioactive iodine is never given in pregnancy.
Graves’ Disease
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Propylthiouracil (PTU) is the drug of choice during the first trimester
(methimazole is the second-line therapy). PTU crosses the placenta and may
cause goiter and hypothyroidism in the fetus, so methimazole is used in the
second and third trimesters. Congenital Graves’ disease in the fetus may be
masked until 7 to 10 days after birth, when the drug’s effect subsides.
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Maternal thyroid-stimulating immunoglobulins (Igs) and thyroid-blocking
Igs can cross the placenta and cause fetal tachycardia, growth restriction,
and goiter.
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PTU and methimazole are Class D drugs that harm the fetus by inhibiting
thyroperoxidase, an enzyme needed to produce T3 and T4.
Diabetes in Pregnancy
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Target values of FBS < 90 mg/dL and < 120 mg/dL 1 hour after a meal.
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Gestational diabetes (GDM) is managed initially with diet and light exercise.
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If target glucose measurements are not met, the drug of choice is insulin.
Insulin requirements increase throughout the course of the pregnancy but
decrease as soon as the placenta is delivered.
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Glyburide and metformin have been used by some in pregnancy.
· · Avoid oral hypoglycemics while breastfeeding, as they can cause hypoglycemia
in neonates.
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