Interventions for hyperthyroidism pre-pregnancy and during pregnancy

Women with hyperthyroidism in pregnancy have increased risks of miscarriage, stillbirth, preterm birth, and intrauterine growth restriction; and they can develop severe pre-eclampsia or placental abruption.

To identify interventions used in the management of hyperthyroidism pre-pregnancy or during pregnancy and to ascertain the impact of these interventions on important maternal, fetal, neonatal and childhood outcomes.

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 September 2013).

We planned to include randomised controlled trials, quasi-randomised controlled trials, and cluster-randomised trials comparing antithyroid interventions for hyperthyroidism pre-pregnancy or during pregnancy with another intervention or no intervention (placebo or no treatment).

Two review authors assessed trial eligibility and planned to assess trial quality and extract the data independently.

No trials were included in the review.

As we did not identify any eligible trials, we are unable to comment on implications for practice, although early identification of hyperthyroidism before pregnancy may allow a woman to choose radioactive iodine therapy or surgery before planning to have a child. Designing and conducting a trial of antithyroid interventions for pregnant women with hyperthyroidism presents formidable challenges. Not only is hyperthyroidism a relatively rare condition, both of the two main drugs used have potential for harm, one for the mother and the other for the child. More observational research is required about the potential harms of methimazole in early pregnancy and about the potential liver damage from propylthiouracil.