The effect of hyperthyroidism in the first trimester of pregnancy on low birth weight

  Aim: The diagnosis of thyrotoxicosis in the first trimester of pregnancy is peculiar due to the physiological changes that occur due to pregnancy. There are maternal and fetal adverse effects of hyperthyroidism on pregnancy. In this study, we aimed to evaluate the effect of thyrotoxicosis on newborn weight in pregnant women with gestational transient thyrotoxicosis or Graves' disease who were referred for thyrotoxicosis in the first trimester. Material and Method: Ninety-four pregnant women in the first trimester with subclinical or overt hyperthyroidism caused by gestational transient thyrotoxicosis or Graves’ disease and 30 healthy pregnant women in the same trimester were included in the study. The birth weights of their babies were compared. Results: Ninety of the patients reached delivery, and four with gestational transient thyrotoxicosis had abortus due to obstetric reasons. No statistical difference was found in terms of the birth weights of the babies in the comparison between the gestational transient thyrotoxicosis, Graves’ disease, and the control groups (p>0.05). Conclusion: In our study, neither gestational transient thyrotoxicosis nor Graves' disease was found to be associated with low birth weight. But since it is known that overt hyperthyroidism may be associated with low birth weight, pregnant women with hyperthyroidism should be followed carefully.