Decreased birth weight, length, and head circumference in children born by women years after treatment for hyperthyroidism

Abstract

Context: Whether hyperthyroidism influences the birth characteristics of children born several years after treatment is unknown. Copyright Objective: The objective of the study was to compare birth characteristics in singleton newborns delivered bywomenpreviously treated for Graves' disease (GD), toxic nodular goiter (TNG), or nontoxic goiter (NTG). Design: This was a nested case-control design within a national cohort registry study from 1950 through 2006. Setting: The study was conducted at a university and a hospital center in collaboration. Patients: The birth characteristics of newborns (n = 3421) delivered in a cohort of 43 633 women treated forGDor toxic nodular goiter by radioiodine or surgery (exposed group) at least 1 year prior to pregnancy were compared with newborns (n = 2914) of 45 655 mothers, previously operated for NTG (unexposed group). Main Outcome: The primary outcome was birth weight, length, and head circumference. The secondary outcome was malformations, gestational age, and type of hyperthyroidism. Results: The birth weight of exposed children was 3431 ± 607 g (mean ± SD) compared with the unexposed, 3520±641 g (P