Does prior hemithyroidectomy influence thyroid function during pregnancy and obstetric outcomes? To investigate this, a retrospective matched cohort study evaluated thyroid and pregnancy outcomes in 463 pregnancies following hemithyroidectomy and 2,293 matched control pregnancies in women without prior thyroid surgery. The study found that prior hemithyroidectomy was associated with higher odds of gestational hypothyroidism (adjusted odds ratio, 4.2).

Although hemithyroidectomy was not associated with an increased hazard of first-trimester pregnancy loss (HR, 0.9), it was associated with a higher hazard of preterm birth or pregnancy loss during the second and third trimesters (HR, 1.6). These findings suggest that prior hemithyroidectomy is associated with an increased likelihood of gestational hypothyroidism and a higher hazard of the composite obstetric outcome during later pregnancy,…