Thyroid Disorders in Pregnancy

Hypothyroidism in Pregnancy

Pt with h/o repeat miscarriage, high-dose neck radiation, DM1 and hypothyroidism presents s/p positive pregnancy test. Reports recent fatigue, weight gain, decreased exercise capacity, and constipation. Bradycardia, dry skin, and hair loss noted on exam.

• Repeat urine pregnancy test

• Obtain TSH, free T4 q4 weeks until 20 WGA; measure again at 24-28 and 32-34 WGA

• Pt instructed to increase levothyroxine by two doses/week prior to dose titration per TSH, free T4

• Titrate levothyroxine to trimester-appropriate TSH

  • 1st: 0.1-2.5

  • 2nd: 0.2-3.0

  • 3rd: 0.3-3.0

• Pt counseled about importance of levothyroxine adherence to reduce risk of miscarriage/preterm birth

• Pt counseled about increased risk for hypertensive disorders and abruption

• Pt counseled about risk for postpartum thyroiditis and how to recognize symptoms of hyper/hypothyroidism

• Resume pre-pregnancy levothyroxine dose postpartum

Hyperthyroidism in Pregnancy

Pt with h/o goiter presents s/p positive pregnancy test. Reports increased nervousness, heat intolerance, and diarrhea. Tachycardia, HTN, sweating, tremor, and proximal muscle weakness on exam.

• Labs show low TSH, elevated free T4

• Propylthiouracil 50 to 200mg BID during 1st trimester

• Methimazole 5-20mg BID during 2nd and 3rd trimester

• Obtain TSH and free thyroxine labs q2 weeks until serum free thyroxine in upper 1/3 of normal range; test weekly after 32 WGA

• Pt counseled about importance of medication adherence to reduce fetal anomalies, heart failure, placental abruption, preeclampsia, and preterm delivery