ATA Guidelines Tools

18 Fetal and Neonatal Considerations Î A history of maternal thyroid illness, use of antithyroid medications (PTU, MMI) during gestation, or measurements of abnormal maternal thyroid function or TRAb during gestation should be communicated to the newborn's neonatologist or pediatrician. (S-M) Î The severity of maternal and fetal thyroid illness should guide the timing of communication. Severe, progressive, or complex thyroid illness during pregnancy mandates communication with the neonatologist or pediatrician before birth and consideration of consultation with a pediatric endocrinologist. Most other illness is optimally communicated shortly after birth. (S-M) Î All newborns should be screened for hypothyroidism by blood spot analysis typically 2–4 days after birth. (S-H) Thyroid Disease and Lactation Î As maternal hypothyroidism can adversely impact lactation, women experiencing poor lactation without other identified causes should have TSH measured to assess for thyroid dysfunction. (W-L) Î Given its adverse impact upon milk production and letdown, subclinical and overt hypothyroidism should be treated in lactating women seeking to breastfeed. (W-L) Î The impact of maternal hyperthyroidism upon lactation is not well understood. Therefore, no recommendation to treat maternal hyperthyroidism on the grounds of improving lactation can be made at this time. (I) Î The use of 131 I is contraindicated during lactation. If required, 123 I can be used if breast milk is pumped and discarded for 3–4 days before breastfeeding is resumed. Similarly, Tc-99m pertechnetate administration requires breast milk to be pumped and discarded during the day of testing. (S-M) Î Excepting treatment decisions specifically made on the grounds of improving lactation (discussed above), the decision to treat hyperthyroidism in lactating women should be guided by the same principles applied to non-lactating women. (S-L) Î When antithyroid medication is indicated for women who are lactating, both MMI (up to maximal dose of 20 mg daily) and PTU (up to maximal dose of 450 mg daily) can be administered. Given a small, but detectable amount of both PTU and MMI transferred into breast milk, the lowest effective does of MMI/carbimazole (CM) or PTU should always be administered. (S-M)

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